# New PM-728V-T Mill



## AlanB

I've wanted to get a small mill for many years, initially I planned on a Grizzly G0704, then changed to a PM25 and considered many others along the way. But the procurement just kept slipping further and further out. I've been "getting by" with a Grizzly G0516 which is a combo 10x21 lathe and Mini Mill which I've had since 2003. The lathe is pretty capable but the Mini Mill is very limiting and the lathe cross slide is rather small and strange for a mill table. I'd like to get a better lathe, but I need the mill too so I really need to upgrade the mill first. Then maybe I'll be looking at lathes...

Recently I decided to just get on with ordering something, and was preparing to order a PM25 when the PM728 popped up. I waited and waited to see them in the field, but nothing was showing up, so finally I bit the bullet and made the order.

A few days before Christmas I got the tracking email and Saia LTL Freight had the package. There were a lot of tracking updates until it departed Chicago late in the week before Christmas, then all updates stopped. There were no estimates of delivery, no updates on where it was, just silence.

The day after Christmas my wife took the call saying it would be at the terminal in a day or two. Still no tracking updates, no estimates online. It hit the terminal early Friday morning and suddenly there were tracking updates online. 

I had requested "hold at terminal", as I had done with the lathe years ago, as it works out better for me. We are on a cul-de-sac and big trucks are not happy delivering here, and my long sloping driveway is not fun to deal with. So I take a small flatbed trailer to the depot, they forklift the crate onto it, and I back it up wherever I want it.  The trailer is much lower than my truck bed, and can be tilted if that is needed.

I made the trek to the Saia depot Friday afternoon and the very helpful people at the depot forked the crate on the pallet onto my trailer. They helped me remove the shipping pallet from under the crate, and I strapped it down thoroughly for the ride home. I screwed some 2x4's to the trailer bed in front to insure it would not slide forward during hard braking. I brought new straps and cranked them down till the crate was complaining so it would not be passing me on the freeway. 







I used a hydraulic lift table to bring the mill from the trailer into the garage and up to workbench height and slide it onto a polyethylene cutting board which I can move easily. All the moving effort has been easy for two adults, no heavy lifting, just sliding an inch or so at a time. The cutting board wants to slide on the bench so I had to keep moving it back under the mill as we progressed. In summary the hydraulic lift table cart was excellent and made the job easy. A shop crane wasn't practical due to the gradient of the driveway and the low clearance under the workbench.







Then I built a temporary gantry and used a hydraulic jack and some threaded rods to lift it and position the drip tray underneath, an easy one man job. Here it has just landed:






So now it is in position on the mobile workbench with plenty of drawers to contain the tooling:






My plans are to use it manually for awhile as I prepare to convert it to CNC. This conversion is not going to be easy as there are no CNC kits available for the new mill. I may do a bootstrap conversion, making 3D printed parts and later converting to machined parts. I have been collecting a lot of the CNC controls parts for awhile so I have a Linux CNC system and Mesa boards as well as closed loop stepper motors and electronics in boxes. I've been doing 3D design and printing for a couple of years but this will be my first CNC conversion, which I've been reading about for years.  

So it begins!


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## tweinke

Congratulations on your new machine. Keep us posted with your impressions of it.


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## rwm

I wonder if some of the 727 CNC hardware would fit directly? Shooter might know.
Robert


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## AlanB

That is a fascinating question..

Looking more closely though they have a lot of small differences.


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## rwm

I'm torn about ordering mine with a DRO since I will also eventually convert to CNC. It would be great to have the DRO in the beginning.
Robert


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## AlanB

I don't think they have DRO yet, or at least they didn't when I ordered. I'm just going to have to wait for CNC to get that.


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## erikmannie

rwm said:


> I'm torn about ordering mine with a DRO since I will also eventually convert to CNC. It would be great to have the DRO in the beginning.
> Robert



I recently bought a PM-25MV mill and PM-1030V lathe and I got the PM factory DRO on both machines. I have had zero problems with the DROs.

I believe that a DRO makes the whole backlash problem go away, at least insofar as determining the position of the workpiece (mill) or tip of cutting tool (lathe).

Just the time saved by not fussing with the handwheels makes the DRO worth the expense. I say this while having absolutely nothing against handwheels.

Alan, what do you think your CNC tool changing system will be?


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## AlanB

I'm using Tormach TTS tooling on my Mini Mill, and I already had the R8 adapter for TTS so that was the second thing I popped in the chuck (after the drill chuck). I have a modest collection of TTS tool holders. Eventually I'd like to put a power drawbar on so I could do automatic tool changing, but that's down the road.

I've never had a DRO so I don't miss it. Yet. The G0516 uses metric leadscrews with imperial dials to it is really hard to keep track of things over more than a turn. This is a big improvement with inch screws so you can count turns.


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## 7milesup

For the price of a Chinese DRO I would install that in a heartbeat.  Here is a Linky to one that I have for my 833T.


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## Maplehead

Just curious, in general terms, how would you compare the 728 to the 727? I'm not looking for all the details but more on what is an overall better machine. (And will it be beefy enough for steel.)


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## erikmannie

Maplehead said:


> Just curious, in general terms, how would you compare the 728 to the 727? I'm not looking for all the details but more on what is an overall better machine. (And will it be beefy enough for steel.)



On the PM website there is a link to a “PM Bench Mills Comparison” chart. One place to find the link is in blue print on the PM-727V item description page. 

However, the PM-728VT is so new that it is not included in the comparison. Hopefully PM will soon update the comparison chart to include this fine new mill.

I recently improved my ability to cut mild steel on my benchtop machine by sharpening the HSS cutting tool, adding even more cutting fluid and further maximizing my rigidity through improved workholding. 

I also keep RPMs as low as possible when I cut steel. 

On a few occasions (cutting steel), I was greedy with the depth of cut and it stalled the machine because the cutting tool was unable to advance. In these cases, I turned off the machine as soon as possible, hoping that I didn’t damage the machine. So far, the machine has always returned to its original operating condition.

When I took machining classes, the school had large, older domestic machine tools. The instructors told us to go no deeper than, say, .030” in a single pass. I never saw those machines stall due to too deep of a cut.


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## AlanB

Maplehead said:


> Just curious, in general terms, how would you compare the 728 to the 727? I'm not looking for all the details but more on what is an overall better machine. (And will it be beefy enough for steel.)



Note that I don't have a 727, so I can only look at information from others.

With similar designs the consensus is that stiffness is related to weight. The 727 is about 27% heavier, but some of this is a heavier motor and gearbox vs the 728's BLDC and belt drive. Still the 727 is a slightly stiffer machine. Both machines are stiff enough to handle steel, as commonly demonstrated by even lighter machines such as the PM25 and G0704. The 728 is from Taiwan where the 727 is from China, and generally it is the case that the Taiwanese machines are a little better in some areas. The 727, being a lower priced machine, is an excellent value. The 728 is a little quieter, has much higher spindle RPM, a little larger workspace, is a little easier to move around and has the convenience of variable speeds vs gear shifting.

These mills are more similar than different. The cost, features or availability of accessories (like CNC kits) may drive the decision in one direction or the other.

Good luck in your decision.


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## Maplehead

Thanks Alan for the reply.
The write-up on the 728 is sort of like the mill is the mill to end all mills. God-like. Are the things like the triple bearings that much better than the 727?
One thing I do lean towards is a belt drive mill. Wish all these models were belt driven. But the 728 is $800 more, 100 pounds less and not DRO ready.
What you think?


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## AlanB

To really answer this I think we'll have to see more actual results from the field. Theory and specs only go so far.


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## mksj

Looks like a very nice mill, look forward to hearing more of your review when it is up and running.

You cannot look at the weight as the sole determining factor as too stiffness, the type of materials, webbing, geometries, etc. all come into play. Weight does help to dampen vibrations. I think as stated the 727/728 machines are more similar than different, the choice is similar to if one wants a PM-1236 heavier lathe vs. PM-1236T which it lighter but has better fit/finish, less change gears, etc. As far as not DRO ready, not sure what is meant by that. You can always install a DRO on these types of mills, you typically need to fabricate your own brackets anyway. Lots of good DRO's these days in the $200-300 range.


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## AlanB

One of the first tasks I have for this mill is to drill and tap some fiber reinforced plastic parts. I used to do this on the G0516's Mini Mill, but they changed the plastic and the Mini no longer has the low speed torque required. Since the tap is tapered it must be precisely stopped so using higher tapping speed doesn't work. I've designed a work holding jig optimized for this mill and here's the first 3D printed draft. It uses heat-set brass threaded inserts for the part hold-down screws, and the spacing of the mounting ear holes matches the T slots in the 728's bed. The pins and ring locate the part repeatably. It is very short which maximizes the Z space for the TTS compression-extension tapping tool. Once I get the right length hardware I'll try this out. The BLDC motor should have good low end torque though it is also dependent on the controller.


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## erikmannie

That looks like a really nice jig. 

How exactly do you put in the heat-set brass threaded inserts?


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## AlanB

With soldering pencil and either a special tip or a regular tip, or with a hot air soldering pencil to heat the brass nut on the end of a long screw, then push it in.

In this particular case I sized the hole just slightly smaller than the nut, so I can pull them in with a screw from the top side. They stop at a shoulder in the hole, since I install the nut from the bottom they can't come through the smaller screw hole. This also allows me to recover the nuts if the plastic is discarded.

If the hole is too small then too much plastic must be displaced and the result can be unusable (it often fouls the threads), so a little experimenting may be needed to find the right tolerances.


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## AlanB

Today I made some chips with the new mill. I drilled,  milled and tapped one of the fiber reinforced plastic parts. The mill and the work holder performed nicely. The drilling and milling worked well, though the center finding was a pain in the neck. A DRO would help there, or a laser center finder.

In power tapping the hole the mill had enough torque to tap at fairly low speed with this large tap in tough plastic. But it is still a bit fast and not well enough controlled, it should be fine for CNC but but not as slow as I'd like for manual.


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## AlanB

3D Printed Design for TTS ER20 Tool Holding Tray for the mill


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## AlanB

Backlash on X and Y seems to be 0.006". The large metal handwheels feel great with a little more friction than I'm used to. There is an adjustment for X and Y backlash but I have not touched any adjustments.


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## StevSmar

Looks like a very nice benchtop mill. I’m enjoying reading your thread!


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## arizonavideo

I do like the look of the mill.

For its size I would expect really good performance with the thicker base and the wide lower column mount.


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## 9t8z28

Very Cool new machine!  Congrats!  Can you tell us about the quill.  Particularly the backlash on the handwheel and the play with the quill extended?


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## jimrk

Pushed the order button yesterday for the 728, and a new acorn board.  Think I'll put my X3 back together (was planning to CNC it) and list it. Could pay for Clearpath servos.


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## AlanB

Great! I seem to see some postings here I missed. I'll have to try and respond to those soon.


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## jimrk

It made it today.  It was well crated, with no damage I can see.  Now the fun begins


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## 9t8z28

Congrats to you as well JimRK.  Maybe you can you tell us about the quill. Particularly the backlash on the handwheel and the play with the quill.


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## jimrk

Planning on CNC so went right to teardown.  Very impressed so far.


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## rwm

I am eventually buying one. Thanks for sharing the pics
Robert


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## Toolmaker335xi

I see you are a lot more motivated on the conversion than I am. I too recently purchased a PM-728vt with plans of converting it to CNC. I think I’m also hesitant to start the tear down from lack of experience since this would be my first conversion. Also knowing I’ll have to disassemble it multiple times in order to machine the parts.

Good luck with your build. I will definitely be following it. Curious to see What the differences are between the the 728 vs the 727 and when someone will be coming out with a kit. I think I’m going to wait for someone to offer a full conversion kit.( the mechanical components, going with a G540 controller and mach3 since I already have them from a Sherline I had) I’m fearful of purchasing the wrong parts and wasting money on something I won’t be able to use.


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## Kyo

Looking good, Always enjoy seeing tear down photos. Gives a better look at the machine vs a stock image. Are you planning on making your own cnc conversion parts or running the Precision Mathews kit? https://www.precisionmatthews.com/shop/pm-728v-t-cncballscrewkit/ apparently last I emailed the 728V-T cnc kit is made by the same factory making the mills. I am looking forward to getting more details when the kits come in. Particularly ballscrew details (class, size, pitch ) , double / single ball nut ect. Will be nice to have a factory offering. Though David's kit on my last pm25 was top notch as well, are you going to be doing kits for the PM728V-T as well @arizonavideo ?


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## jimrk

Toolmaker335xi said:


> I see you are a lot more motivated on the conversion than I am. I too recently purchased a PM-728vt with plans of converting it to CNC. I think I’m also hesitant to start the tear down from lack of experience since this would be my first conversion. Also knowing I’ll have to disassemble it multiple times in order to machine the parts.
> 
> Good luck with your build. I will definitely be following it. Curious to see What the differences are between the the 728 vs the 727 and when someone will be coming out with a kit. I think I’m going to wait for someone to offer a full conversion kit.( the mechanical components, going with a G540 controller and mach3 since I already have them from a Sherline I had) I’m fearful of purchasing the wrong parts and wasting money on something I won’t be able to use.



I did feel a little bad about tearing such a nice machine down without even using it but need to keep going forward.
Will be interesting to see what Franco comes up with on his.


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## Toolmaker335xi

Kyo said:


> Looking good, Always enjoy seeing tear down photos. Gives a better look at the machine vs a stock image. Are you planning on making your own cnc conversion parts or running the Precision Mathews kit? https://www.precisionmatthews.com/shop/pm-728v-t-cncballscrewkit/ apparently last I emailed the 728V-T cnc kit is made by the same factory making the mills. I am looking forward to getting more details when the kits come in. Particularly ballscrew details (class, size, pitch ) , double / single ball nut ect. Will be nice to have a factory offering. Though David's kit on my last pm25 was top notch as well, are you going to be doing kits for the PM728V-T as well @arizonavideo ?


I didn’t know they were offering a kit. Too bad it’s not available right now. Does any one know of one available already?


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## jimrk

Kyo said:


> Looking good, Always enjoy seeing tear down photos. Gives a better look at the machine vs a stock image. Are you planning on making your own cnc conversion parts or running the Precision Mathews kit? https://www.precisionmatthews.com/shop/pm-728v-t-cncballscrewkit/ apparently last I emailed the 728V-T cnc kit is made by the same factory making the mills. I am looking forward to getting more details when the kits come in. Particularly ballscrew details (class, size, pitch ) , double / single ball nut ect. Will be nice to have a factory offering. Though David's kit on my last pm25 was top notch as well, are you going to be doing kits for the PM728V-T as well @arizonavideo ?



Thinking of DIY for now.  Matt has it listed at end of July and I don't want to wait.  I follow Sam (CNC4XR7) and Franco, thinking I'll do a little of both.
Plan on 2005 C7 and double ballnuts from linearmotionbearings2008.  Might do the FK mounts as Franco did on his PM-25. This is what I'm thinking with different lengths. https://www.ebay.com/itm/X-Y-Z-ball...474563?hash=item3b3b54a943:g:rwsAAOSwRY1dsO6y  working on lengths now to send to Chai for a quote.

Plan on doing nema-23 on X , Y and nema 34 for Z.  That is what Matts kit will be so if my DIY not good they will work on it.  Have not pulled the trigger on closed loop steppers (Franco) or Clearpath $$.  My guess is David would not do one if Matt is importing one around same price point.


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## AlanB

I looked for other kits, the one vendor I contacted said they weren't going to do one because Matt had told them he would have one. If anyone is aware of other kits I'd like to see more about them. If anyone does a DIY hopefully they will share some of their experience somewhere.


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## Toolmaker335xi

jimrk said:


> Thinking of DIY for now.  Matt has it listed at end of July and I don't want to wait.  I follow Sam (CNC4XR7) and Franco, thinking I'll do a little of both.
> Plan on 2005 C7 and double ballnuts from linearmotionbearings2008.  Might do the FK mounts as Franco did on his PM-25. This is what I'm thinking with different lengths. https://www.ebay.com/itm/X-Y-Z-ball...474563?hash=item3b3b54a943:g:rwsAAOSwRY1dsO6y  working on lengths now to send to Chai for a quote.
> 
> Plan on doing nema-23 on X , Y and nema 34 for Z.  That is what Matts kit will be so if my DIY not good they will work on it.  Have not pulled the trigger on closed loop steppers (Franco) or Clearpath $$.  My guess is David would not do one if Matt is importing one around same price point.


I should have read this beforehand. Just ordered PM’s kit assuming I could use the nema 34’s I already have.   hope fully I can make some kind of adapters to hold them.


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## 9t8z28

Everytime I see photos of these bench mills I am amazed at their size.  The castings are sure to add dampening and rigidity and the work they put into the sliding surfaces is sure to add accuracy.


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## 9t8z28

Does the one shot oiler come standard?


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## AlanB

One shot oiler is standard on this mill.


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## AlanB

I have closed loop Nema 23 steppers, so I'll have to get one Nema 34 for Z. Oh Well, having an extra closed loop stepper is not such a bad thing.


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## jimrk

I printed a 2005 ball nut and mount for a mockup. The leadscrews are 20mm so using them to test.  The Y has plenty of travel and look at X, plenty of room.  The X mount is printing as I type.  Waiting is not my strong suit.   When PM says their kit will be a drop in I believe it.  I don't think it could get any better.  The Screws, double nuts, and FK-15 mounts have been ordered from Chai.


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## 9t8z28

Did you check the tram of the spindle to the table before you tore it down?  I know you can easily adjust the tilt side to side but the nod I believe would need to be shimmed where the base meets the column.  I'm just curious how well it was set-up straight from the factory.


jimrk said:


> Planning on CNC so went right to teardown.  Very impressed so far.


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## 9t8z28

I guess the quill tolerances aren't any concern to anyone who are converting their 728V-T's to CNC as it won't be used.  I would assume that''s why my question is of little importance.  I only ask this because I have read several other threads about the various models of PM bench mills and the one complaint they all have is the slop between the quill and spindle and the backlash in the gearing for the quill.  I guess I am the lone wolf on this forum, most of the threads in this section are about converting these mills to CNC.  I am interested in these mills as an alternative to a manual Bridgeport type mill.  Hopefully someone will chime in.  Thanks


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## jimrk

Waiting on hardware so used my printer some more.  The Acorn board has a good setup for reading spindle RPM so looking for options to drive the encoder.  This should work. Also could place it straight ahead for less overhang.  Want to do a PDB and have them play nice together.


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## jimrk

Proof of concept. It will spin




Your browser is not able to display this video.


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## LucidCnC

This in my first post and my first mill PM728 I haven't taken it out of the crate yet as i'm waiting for CNC kit to become available before getting into it so i'll be watching this thread and forum for content and knowledge.

The photos already posted are very helpful, lets me know what to expect.


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## mneblett

LucidCnC said:


> This in my first post and my first mill PM728 I haven't taken it out of the crate yet as i'm waiting for CNC kit to become available before getting into it so i'll be watching this thread and forum for content and knowledge.
> 
> The photos already posted are very helpful, lets me know what to expect.


Ditto -- except no crate in hand yet, as my 728 w/DRO is still on the proverbial "slow boat from China."  In the meantime, I have used the photos that have been posted to figure out how much space to clear for the 728 and a 1030 lathe, while awaiting the arrival of the shipping fairy's delivery truck.  So, thanks for the posts!

The waiting is driving me nucking futz!  (but no problem with PM's service -- can't blame them for transport/customs/virus issues beyond their control)


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## Perch

mneblett said:


> Ditto -- except no crate in hand yet, as my 728 w/DRO is still on the proverbial "slow boat from China."  In the meantime, I have used the photos that have been posted to figure out how much space to clear for the 728 and a 1030 lathe, while awaiting the arrival of the shipping fairy's delivery truck.  So, thanks for the posts!
> 
> The waiting is driving me nucking futz!  (but no problem with PM's service -- can't blame them for transport/customs/virus issues beyond their control)


I'm in the same boat as you, ordered it with the DRO so have been waiting patiently as I can.  
  I don't have any plans for CNC though as ill mostly be using it for hobby gunsmithing and probably a motorcycle part/bracket or two when needed.  Assuming I get decent using a mill as I have absolutely 0 experience with any mill lol.  Also don't know how to program CNC so would be lost there..


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## jimrk

Good to learn manual before CNC. Anyone can use CAD/CAM and push buttons but better to know what you are doing first.


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## bcrosby

I, too, am waiting on a PM-728V-T with DRO. For those who are interested, the following link will let you follow the progress of the container ship that is carrying our mills! https://www.vesselfinder.com/?imo=9786736 It's scheduled to dock in New York on Friday of this coming week! Not that I'm anxious or anything like that . . .


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## rwm

That map is the coolest thing I have ever seen.
Robert


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## DaveV

bcrosby said:


> I, too, am waiting on a PM-728V-T with DRO. For those who are interested, the following link will let you follow the progress of the container ship that is carrying our mills! https://www.vesselfinder.com/?imo=9786736 It's scheduled to dock in New York on Friday of this coming week! Not that I'm anxious or anything like that . . .


Incredible map!  Thank you for sharing.


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## jimrk

Finally connected the encoder to the Acorn board to test proof of concept. It works.


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## Perch

bcrosby said:


> I, too, am waiting on a PM-728V-T with DRO. For those who are interested, the following link will let you follow the progress of the container ship that is carrying our mills! https://www.vesselfinder.com/?imo=9786736 It's scheduled to dock in New York on Friday of this coming week! Not that I'm anxious or anything like that . . .


Nice, Thanks for the info!  Hopefully there isn't a problem at customs.


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## rwm

Not sure if the map is updating but it doesn't look like the Osprey is going to make NYC by Friday?
Robert


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## Buffalo21

The map shows where the ship was on the 6/1/20, that date is on the screen


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## LucidCnC

You can see them on marinetraffic . com it's another AIS site which at this time is showing them to be steaming along at 17knts


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## Perch

rwm said:


> Not sure if the map is updating but it doesn't look like the Osprey is going to make NYC by Friday?
> Robert


Actually just updated location about 1hr. Ago.. should be there tomorrow!


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## Skowinski

Hi Guys - sort of off the last topic of discussion here, but - any thoughts/experiences with the quality of the PM Taiwan-made vs PM Chinese-made machines?  Looks like in general the Taiwanese machines are about $1000 or so more than the equivalent Chinese machines, e.g. 728 vs 727 models.  Is the quality and accuracy that much better, worth the cost?


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## Perch

Skowinski said:


> Hi Guys - sort of off the last topic of discussion here, but - any thoughts/experiences with the quality of the PM Taiwan-made vs PM Chinese-made machines?  Looks like in general the Taiwanese machines are about $1000 or so more than the equivalent Chinese machines, e.g. 728 vs 727 models.  Is the quality and accuracy that much better, worth the cost?


No first hand experience with either, but plenty of first hand experience with both "made in China" and "made in Taiwan" tools, parts, toys, etc. And no matter what it is, Chinese manufactured anything always seems to be lacking in either assembly, quality of parts, or quality control.  Alot of the time its 2 of the 3.  Thats my "experience" anyway.


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## jimrk

Now that I have the Control box 99% complete I've started on the hardware.  Have the Y working.  Have a video of it but uploading on cellular is VERY slow.  When I get to a location that has some speed I'll upload.

Worked on the X today.  Used a standard 2005 ballscrew mount (drilled new holes for the existing holes in the table)






	

		
			
		

		
	
F

Printed a mount for the servo end that holds the FK15 bearing mount.






A slight oops with the ball screw dimensions I requested.  Not enough threads for two lock nuts.  Have some thinner ones of the way from McMaster.
Pretty happy with getting the X to line up on the first try.  Pretty much copied the original dimensions.

Free end will have a FF15 mounted to this mount






And this is the Y setup. Both printed and machined parts


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## jimrk

Have X and Y in motion


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## rwm

Now that's what I call a great Saturday!
Robert


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## jimrk

rwm said:


> Now that's what I call a great Saturday!
> Robert



Beer:30 now


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## Perch

Skowinski said:


> Hi Guys - sort of off the last topic of discussion here, but - any thoughts/experiences with the quality of the PM Taiwan-made vs PM Chinese-made machines?  Looks like in general the Taiwanese machines are about $1000 or so more than the equivalent Chinese machines, e.g. 728 vs 727 models.  Is the quality and accuracy that much better, worth the cost?


With regard to the PM727/PM728 and if its worth the extra ~1k I don't know for sure as I've never seen either one but I do know when comparing all the other Chinese products I've gotten over the years they always have something wrong with them.  Whether its bad assembly, bad manufacturing process, sub-par metal, or bad design it more often than not had at least 1 of the 4 things I listed wrong with it.  
  Regarding Taiwanese products I've gotten over the years most are well made with only 1 occasionally having 1 of the issues listed.  
  With that in mind and considering the amount of money I'm spending on one of these machines, I spent the extra 1k and got the 728.  I'd rather spend a bit more and have a better quality machine than save a bit and possibly have issues with a brand new machine/not long after purchase. 
   If I had experience working on vertical mills and improving/restoring them id consider the 727, but without that experience I'd rather play it safe.


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## MachinistsSon

My first post...

So my search for an affordable, capable garage CNC mill has led me here.  What I think I want is a PM 728 with an Acorn controller, made in the PM factory.  Manual/CNC capability would be cool as well.  Anyone know if PM is doing this, or what CNC plans they have for these mills? I see the addons on the web site available in July, so there must be CNC demand.  (Please don't violate NDAs).


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## jimrk

MachinistsSon said:


> My first post...
> 
> So my search for an affordable, capable garage CNC mill has led me here.  What I think I want is a PM 728 with an Acorn controller, made in the PM factory.  Manual/CNC capability would be cool as well.  Anyone know if PM is doing this, or what CNC plans they have for these mills? I see the addons on the web site available in July, so there must be CNC demand.  (Please don't violate NDAs).



I have no clue but WAG is they will only be adding the CNC hardware.  Building the Acorn controller is "pretty simple".  Just follow what other have done and you will be fine.  I might get a wiring diagram drawn up at some point.


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## MachinistsSon

It's not that I don't think I can build the Acorn, it's that this is my first personal machine, and I don't really want to/not really sure I have the equipment to do the modifications.  After I have an operational machine, I'd be more open to upgrading another machine, I guess.

Does a factory installed Centroid on a PM-728V-T makes sense?  I've been reading/watching a lot lately, and this combo just seems to make sense to me, but I'm in no way an expert in manufacturing or immersed in the field, hence the questions.

It seems a little odd that PM would have CNC upgrade parts available, but not go the final step to offer a complete CNCed 728.  Leaves me kind of puzzled...  Maybe there's just not a big enough market.

What's WAG?  I haven't heard that one before.


----------



## jimrk

MachinistsSon said:


> It's not that I don't think I can build the Acorn, it's that this is my first personal machine, and I don't really want to/not really sure I have the equipment to do the modifications.  After I have an operational machine, I'd be more open to upgrading another machine, I guess.
> 
> Does a factory installed Centroid on a PM-728V-T makes sense?  I've been reading/watching a lot lately, and this combo just seems to make sense to me, but I'm in no way an expert in manufacturing or immersed in the field, hence the questions.
> 
> It seems a little odd that PM would have CNC upgrade parts available, but not go the final step to offer a complete CNCed 728.  Leaves me kind of puzzled...  Maybe there's just not a big enough market.
> 
> What's WAG?  I haven't heard that one before.



I does but PM is more into selling 'hardware'.  The fact they are (soon) selling the CNC parts is cool.  To get a full blown CNC setup there are other vendors (Tormach).  There are many options for motors and controllers.  I've used steppers and drivers with Mach3 in the past.  I used the Acorn with steppers on my G0602 build and liked the Acorn.
I stepped up on this build to Clearpath and Acorn.  I'm into it around $6,000 and have a bit more to go. I have about $250 into the CNC ball screws. I didn't want to wait.  Might get them if my setup does not cut it, I'm in deep already so another $800 will not be a huge deal)
If you add the PM parts and Acorn you would be in the $4600 range and add controller setup gets the price up there.

You may be correct with not enough market for PM to source a controller setup.  You should email Matt and see if he has considered it.

You must be a young fella, WAG = Wild Ass Guess


----------



## MachinistsSon

Not young... just seem to have missed that one, somehow.

The Tormachs look out of my price range.  Think I'll keep reading some more...


----------



## rwm

I just bought one!
Robert


----------



## rwm

Robert


----------



## jimrk

rwm said:


> View attachment 329232
> 
> 
> Robert


Don't you wish everything was crated as well?  Saved mine for who knows what, just too nice not to.


----------



## Tio Loco

Mine's on the truck somewhere south of Charlotte.  Can't wait...


----------



## rwm

I have not fully set up this mill yet, but I found one thing I don't particularly like. The coarse feed on the spindle feels very rough. I can feel the tooth engagement on the column and it feels like an old cheap Chinese drill press. I do not think this will affect function but it is certainly not as smooth as my Clausing drill press or any old worn out Bridgeport I have used. Can someone else who owns the 728 comment here? Does your coarse feed feel similar? 
Robert


----------



## AlanB

I'm looking forward to the PM-728 CNC hardware kit. I for one would not want any particular electronics package included, there are too many choices in motors, electronics and software. I've already collected most of that but a bolt-in hardware kit would really reduce the risk and effort of the mechanics. It's July now so hopefully we're getting close on this kit.


----------



## Tio Loco

A thing of beauty...






Could some of you youngsters come over to help pick it up and put it on the base?

On a side note, in anticipation of receiving this mill, I purchased a Kurt DX4, all I can say is wow! Light years different from my 3" generic import.


----------



## jimrk

Made some progress on the Z.


----------



## rwm

Hey Tio Loco- could you comment on the smoothness of your spindle feed with the large handles.

Robert


----------



## Tio Loco

@rwm Sure, I checked that after reading your post, and I don't notice any symptoms that you reported. Assuming you mean the quill feed, it's very smooth. I don't feel any tooth engagement at all.


----------



## chipping

AlanB said:


> I'm looking forward to the PM-728 CNC hardware kit. I for one would not want any particular electronics package included, there are too many choices in motors, electronics and software. I've already collected most of that but a bolt-in hardware kit would really reduce the risk and effort of the mechanics. It's July now so hopefully we're getting close on this kit.


Previously listed as end of July, now listed as "ETA Sept/Oct 2020."  Hopefully the manual will be posted earlier, to get an idea of what is involved.


----------



## jimrk

I Scored big ($90)
Recycle place had two of these frames.  I got one, missed out on the other. 
Heavy 2" tubing (224lbs).  Almost a match of the PM gray.  Now I need to plan the pan & enclosure.


----------



## jimrk

Made more progress today.   Got the mill moved to the new table and put the head back on.


----------



## jimrk

Have been working on it.  Have the Home switches installed.  Printed a mount for the Z that filled the void from the Z crank.
Tried to KISS.  The switch has a long arm so it ended up with backoff more than it should be but will work.






Printed a cover for the X switch






Mounted the Y to a piece of angle.  Might need to print one to match the others 





Glad I used a board from CNC4PC to connect the Clearpath servos to the Acorn.  The Z servo has an issue with no holding power when not enabled (the head will drop when turned off or disabled).  The board has a setting for hardware or software enable.  If software is used the head can drop when 'reset'.  Switched to the hardware setting and seemed to solve the issue.


----------



## Overkill777

Thanks for posting pics. I'm following the thread very closely since I'm thinking about buying one of these. 

If I do I will learn how to run it manually and I would like to do a CNC conversion in the future so this is all very interesting!


----------



## jimrk

Been sidetracked but working on an enclosure of sorts. Mostly to keep chips in.  Maybe some mist, not planning on flood but we shall see.
KISS, used 80-20 extrusion for top and bottom rails for both sides and front doors.  I have plenty of room left and right so the doors just slide out. The Sides can slide out also to gain access when needed.
1/4" polycarbonate for front and sides.  Corrugated plastic in the back but thinking polycarbonate for that also.


----------



## rwm

That looks great. Excellent idea to use 80-20. Why is it called that anyway?
Robert


----------



## jimrk

rwm said:


> That looks great. Excellent idea to use 80-20. Why is it called that anyway?
> Robert


It's the name of the company 








						T-slot structural framing - Wikipedia
					






					en.wikipedia.org


----------



## rwm

Interesting. This is actually the origin:








						Pareto principle - Wikipedia
					






					en.wikipedia.org
				



Robert


----------



## Tio Loco

@jimrk I don't really have an interest in a CNC conversion, but I would like to add a power feed to the Z axis. My mill setup is a bit of a stretch to reach and use the hand wheel comfortably.

Would you be so kind as to share specifically which ClearPath NEMA 34 motor you selected for your Z axis?  If my understanding is correct, using the ClearPath motor and a suitable power supply, I can build a simple controller using an Arduino (or other microcontroller) in conjunction with a rotary encoder. Am I missing something there?

Also, could you share your thoughts on your inline mount instead of a geared mount replacing the hand wheel? I'm assuming it is related to replacing the lead screw with a ball screw? 

For my application, I'm assuming that the stock lead screw will be fine since it will be a 'manual' setting and gravity will compensate for backlash.


----------



## rwm

Tio- I am trying to do this also. I really don't want to learn how to program and arduino just to do this. Is there a simpler way that still uses a stepper?
Robert


----------



## jimrk

Tio Loco said:


> @jimrk I don't really have an interest in a CNC conversion, but I would like to add a power feed to the Z axis. My mill setup is a bit of a stretch to reach and use the hand wheel comfortably.
> 
> Would you be so kind as to share specifically which ClearPath NEMA 34 motor you selected for your Z axis?  If my understanding is correct, using the ClearPath motor and a suitable power supply, I can build a simple controller using an Arduino (or other microcontroller) in conjunction with a rotary encoder. Am I missing something there?
> 
> Also, could you share your thoughts on your inline mount instead of a geared mount replacing the hand wheel? I'm assuming it is related to replacing the lead screw with a ball screw?
> 
> For my application, I'm assuming that the stock lead screw will be fine since it will be a 'manual' setting and gravity will compensate for backlash.



The ClearPath I used is CPM-SDSK-3432S-RLN ($387)

Have you checked what Priest Tools has? 





I don't see it listed on his site but I would guess about the same cost of the  other ones ($299). The site also has installation docs so you can see what he is doing.


----------



## AlanB

A stepper motor would probably be a better choice for a simple motorized Z axis (it is a long reach for the crank), the servo is expensive and when turned off has little holding torque. They both require step pulses and a direction signal. A small microcontroller can easily convert the two quadrature signals from an encoder knob to step and direction, or generate other pulse sequences from buttons, toggle switches, etc. similar to a power feed.


----------



## Tio Loco

@rwm That's the problem, there are so many ways to approach this problem, but for steppers or servo motors something is needed to generate the pulses and direction and the Arduino is a very affordable and relatively easy solution. DroneBot Workshop has a couple of tutorials addressing this approach:









						Stepper Motors with Arduino – Bipolar & Unipolar
					

Learn how to control bipolar and unipolar stepper motors with an Arduino using drivers like the ULN2003, L298N and A4988.




					dronebotworkshop.com
				




And more to the point of this project:








						Using BIG Stepper Motors with Arduino | DroneBot Workshop
					

Learn how to use a large stepper motor with a microstep driver and an Arduino. We’ll add a potentiometer to control speed and a push button switch to change direction.




					dronebotworkshop.com
				




My concern at this point is getting a motor with enough torque and precision to do the job.

@jimrk Thanks for that. Looks like a very affordable solution assuming that it is the same  price as his other power lifts. My concern there is with accuracy. Ideally I'd like a jog wheel control that would allow me to set the head as precisely as I can currently with the hand wheel and from his videos, I'm not sure that is possible. It seems like more of a 'big picture' movement system. I know, picky, picky, picky.

@AlanB Thanks for the input. I had just been reading about the ClearPath motors and their claim to significantly more power and torque vs. similar sized steppers, but hadn't considered holding power. I'm not sure how significant that would be if I did something like the Priest Tools design, where the manual hand wheel stays in the equation as the manual wheel is sufficient to hold the head in place once set, and particularly after the head is locked.

I sincerely appreciate any and all additional input on this project. I don't mind the lather, rinse, repeat development model for little stuff, but this has the potential to get expensive if not done correctly the first time.


----------



## rwm

Tio- Thanks for that link! That explains a lot. 
However if I understand it correctly, using an Arduino to control this is way over kill!  Why can't I just use a variable pulse generator to supply the PUL input and use mechanical switches to activate the direction and enable? That would be a very minimal effort. Perhaps I am missing something here?
Robert


----------



## jimrk

Tio Loco said:


> @rwm That's the problem, there are so many ways to approach this problem, but for steppers or servo motors something is needed to generate the pulses and direction and the Arduino is a very affordable and relatively easy solution. DroneBot Workshop has a couple of tutorials addressing this approach:
> 
> 
> 
> 
> 
> 
> 
> 
> 
> Stepper Motors with Arduino – Bipolar & Unipolar
> 
> 
> Learn how to control bipolar and unipolar stepper motors with an Arduino using drivers like the ULN2003, L298N and A4988.
> 
> 
> 
> 
> dronebotworkshop.com
> 
> 
> 
> 
> 
> And more to the point of this project:
> 
> 
> 
> 
> 
> 
> 
> 
> Using BIG Stepper Motors with Arduino | DroneBot Workshop
> 
> 
> Learn how to use a large stepper motor with a microstep driver and an Arduino. We’ll add a potentiometer to control speed and a push button switch to change direction.
> 
> 
> 
> 
> dronebotworkshop.com
> 
> 
> 
> 
> 
> My concern at this point is getting a motor with enough torque and precision to do the job.
> 
> @jimrk Thanks for that. Looks like a very affordable solution assuming that it is the same  price as his other power lifts. My concern there is with accuracy. Ideally I'd like a jog wheel control that would allow me to set the head as precisely as I can currently with the hand wheel and from his videos, I'm not sure that is possible. It seems like more of a 'big picture' movement system. I know, picky, picky, picky.
> 
> @AlanB Thanks for the input. I had just been reading about the ClearPath motors and their claim to significantly more power and torque vs. similar sized steppers, but hadn't considered holding power. I'm not sure how significant that would be if I did something like the Priest Tools design, where the manual hand wheel stays in the equation as the manual wheel is sufficient to hold the head in place once set, and particularly after the head is locked.
> 
> I sincerely appreciate any and all additional input on this project. I don't mind the lather, rinse, repeat development model for little stuff, but this has the potential to get expensive if not done correctly the first time.



I forgot about the holding power of the servo.  I do need to remember to lock the Z or it can/will drop.  On the good, the servo it will raise the head even when locked.  With the crank left in place it should not be a problem.  Being an old guy and shrinking I understand making life easier is good.  I have an X3 with the Z crank on the base it's still a PITA.  
Cheap/easy might be just take the hand wheel off and hook up a drill to the shaft.  Height could be an issue still but just putting it out there.


----------



## AlanB

There are many ways you could generate a step and direction signal for a stepper or servo. Probably the best model of what is wanted here is a CNC Pendant or MPG. These tend to generate serial or USB outputs that need to be converted to step/direction. This would be a good job for an Arduino or a Raspberry Pi. Overkill is probably not the right way to think about using these components. They are low cost tools that can make a very simple solution. Raspberry Pi boards start at five bucks and some Arduinos are much less. The real question is what does one want for a user interface. Perhaps a knob so you can rock the position back and forth. Maybe a rate control to reduce the amount of twisting needed to move farther. How about some constant rates for slewing slow or fast, like jog speed and direction. A small micro board could do these things with less hardware and less effort than a bunch of chips (the way we used to do it). So instead of a pile of parts it's just one small module, a couple of wires and a bit of code. But you can do it many different ways. With the micro you could change your mind without having to redesign hardware. And learning something new is always fun!


----------



## rwm

You know....the drill on the shaft is not a bad idea.... That's the kind of simplicity I am looking for here. Unfortunately the shaft is too large for my hand drill. I may make an adapter.
For computer guys who already know Arduino or Rasp Pi its pretty easy to throw that solution out. I do not want to spend the time getting up to speed on that. It would take more effort than you think.
Can somebody shoot down my idea of using a 555 timer with a potentiometer and a couple of switches?
Robert


----------



## jimrk

rwm said:


> You know....the drill on the shaft is not a bad idea.... That's the kind of simplicity I am looking for here. Unfortunately the shaft is too large for my hand drill. I may make an adapter.
> For computer guys who already know Arduino or Rasp Pi its pretty easy to throw that solution out. I do not want to spend the time getting up to speed on that. It would take more effort than you think.
> Can somebody shoot down my idea of using a 555 timer witcoh a potentiometer and a couple of switches?
> Robert


could try a tweak on the handwheel to make a 'nut' and use a socket on the drill.


----------



## jimrk

This might do the trick. I can send Fusion-360 model or could send the part, I have no need for it.


----------



## rwm

Jimrk- that is a very generous offer! Let me see how far I get with the stepper setup. I'm kind of anxious to do that as a learning and experimenting process.
Robert


----------



## jimrk

rwm said:


> Jimrk- that is a very generous offer! Let me see how far I get with the stepper setup. I'm kind of anxious to do that as a learning and experimenting process.
> Robert


Very good.


----------



## jimrk

Finally made some chips.  
Working on a Power Draw Bar.  Fabco-air cylinder from Ebay (MP4X1X4X1FT).  Made some standoffs for the lift plate that use the existing cylinder rods.





Printed a Mock up of the tophat that will thread onto the spindle.


----------



## rwm

Slick. Is that going to be used for R8 collets?
Robert


----------



## jimrk

rwm said:


> Slick. Is that going to be used for R8 collets?
> Robert


Tormach tool system is the plan.  A special R8 3/4"


----------



## AlanB

rwm said:


> ...
> Can somebody shoot down my idea of using a 555 timer with a potentiometer and a couple of switches?
> Robert



With a pot on a 555 you get a range of pulse rates. It goes from fast to slow, but not zero (stop). A couple of switches will give you direction and move/stop. I'd prefer a knob interface to that myself, but whatever you want. You could always choose a picaxe chip and program it in basic, or one of the circuit python boards if you'd rather use Python. 

These days with Arduino or any of these little programmable modules you can always find someone else has already done almost exactly what you want to do, so you start with their project and modify it as needed. So it doesn't require starting from scratch. It just depends on what you want the user interface to be.  The crank that's there is a nice user interface. Perhaps if it is too high make a chain drive on a couple of sprockets and bring it lower.


----------



## jimrk

Plugging away a bit at a time.  PDB is coming along.  Made lots of chips doing the lift plate and sides.  Need to move the motor back a bit. Have a  longer belt that should do the trick.  I think the encoder will work well right in front.  Have a drawbar nut complete so next will be the tophat.  Need to make a BIG sign.. ZERO THE Z YOU IDIOT!


----------



## kiloseven

9t8z28 said:


> I guess the quill tolerances aren't any concern to anyone who are converting their 728V-T's to CNC as it won't be used.  I would assume that''s why my question is of little importance.  I only ask this because I have read several other threads about the various models of PM bench mills and the one complaint they all have is the slop between the quill and spindle and the backlash in the gearing for the quill.  I guess I am the lone wolf on this forum, most of the threads in this section are about converting these mills to CNC.  I am interested in these mills as an alternative to a manual Bridgeport type mill.  Hopefully someone will chime in.  Thanks


Hi, The 728VT is no exception to quill slop. Even drilling vertical , with no side milling , you have to watch it. After all its only 400 lbs or less. For CNC on the 728VT I have definitely locked the spindle all the way up. I tried to bore , using a adjustable boring bar with limited results. If you use the upper travel of the spindle , with the offset boring operation, I get ok results. Using the mill by hand results in mostly accurate cuts in all directions. All quill table top mills, like you indicated, have the quill weakness. Don't get me wrong , I have owned the mill since they came out at PM. A decent Manual mill . A decent CNC as well , Centroid Acorn, Clearpath nema 34's , And I used the PM727 Double ball screw kit from Chai. I only had to trim the screws slightly.
Cheers


----------



## currinh

I think all these options for providing a single stepper like motor with step and direction pulses are valid. But don't you also need a stepper driver and power supply? Those would add considerably more cost than an Arduino, but require no programming.

Just read through the thread and no-one mentioned these "add ons".

Thanks.

Hugh



rwm said:


> Tio- Thanks for that link! That explains a lot.
> However if I understand it correctly, using an Arduino to control this is way over kill!  Why can't I just use a variable pulse generator to supply the PUL input and use mechanical switches to activate the direction and enable? That would be a very minimal effort. Perhaps I am missing something here?
> Robert


----------



## currinh

I have a PM728T that was delivered in June (if I remember the date). The reason I got it is for CNC conversion. I also purchased a PM1022 lathe around the same time, also for CNC conversion. The lathe was delayed and finally delivered Sept. 8. My plan was to do these conversions over the summer. A lot of work to be done so I ordered a PM CNC conversion kit for the PM 728 to speed that one up! If the kit doesn't become available soon I'll likely cancel that order and do my own conversion. Last I heard, these kits are due out sometime in Oct.

I'm working towards the PM1022 conversion. The available space for a conversion look a lot tighter than for the 728. It is starting to look possible though.

jimrk: You are doing a very nice job on your 728 conversion. It's the first conversion I've seen come to fruition. It seems to be moving along rapidly in my estimation. Congratulations. If I may, I'd like to ask a few questions. First, is there any possibility of getting drawings/sketches of yours? Did you use 2005 double nut ball screws on all three axes? Did you have to move the lead screw axes or are they in line with the stock screws, i.e. could you have used the stock end plates? You mentioned the Clearpath stepper motor used for Z above. Did you use the same spec motors for the X and Y? Thank you for any info you can provide.

If I do the conversion myself my current thinking is to use fairly short NEMA 34 steppers for X and Y. Mount these towards/under the machine, rather than sticking out, with a timing belt drive. For my application space is absolutely critical. For electronics likely LinuxCNC, Mesa cards, and Gecko stepper drivers.

Glad I found some CNC content in this thread. Thanks.

Hugh



jimrk said:


> Plugging away a bit at a time.


----------



## jimrk

Have been slowed down by Wild Fires in my area.  We were VERY lucky and had no damage but were evacuated.  Have a Power Draw Bar sorta working.  Tormach R8 holder on order.


----------



## rwm

That is awesome! Can you provide some more detail on how this works? I assume there is a spring holding the drawbar up tight and the cylinder pushes down on the drawbar against the srping? How much pre-load does the spring provide?
Also, I don't know if you noticed but the entire assembly lifted off the mill in that video! You better tighten something!
Robert

Edit: Sorry, I see now that it is spring loaded so it can lift up. Why was that necessary? Couldn't you just shorten the stroke? I wonder if you could do this with a linear stepper rather than an air cylinder?
Robert


----------



## jimrk

There are plenty of examples of how this works.  Hoss might have been one of the early ones.  Priest tools has good vids as does Sam (CNC4XR7)






Belview washers are used to hold the tool holder in the R8 collet, then the air cylinder pushes between the draw bar and a plate to compress them more.  Like unscrewing the drawbar with no forces on the spindle bearings


----------



## rwm

OK! Thank you. that video was very illustrative. I have never understood these in the past. I see now that the objective is to avoid putting force on the spindle bearings. I also see that the forces required would exceed what could be provided by a linear actuator. I have some ideas on this however!
I would have thought that the spindle bearings could handle this downforce? 
Robert


----------



## jimrk

Made the tophat out of aluminum for testing.  Added a steel collar to keep the new drawbar centered.






encoder will be in the front somehow


----------



## jimrk

Working on the encoder mount.  Used a PDB plate that had an oops.  Hole was correct size to fit the encoder so reuse it. Liking the Super glue trick for fixturing.

Cut slots in the side plates for it to slide in and out with a set screw to keep it in place.


----------



## jimrk

Find a belt that will work and then cut the front part off and make it pretty


----------



## rwm

Jimrc- What is the plan/need for the encoder? Do you need the spindle position for threading or some other operation?
Robert


----------



## jimrk

Correct, along with speeds & feeds.  It's easy with the Acorn board so might as well.


----------



## mrosso

jimrk said:


> Correct, along with speeds & feeds.  It's easy with the Acorn board so might as well.


Has anyone created a 3D model of the PM-728vt? I see cad models of the G0704 and the PM-25 out there. It would be great to have a Fusion 360 model of the 728 to work out things like limit switches, encoder mounts, stepper/servo mounts, etc. Great work on your build, by the way.


----------



## jimrk

Not that I know of.  Some of what I did was 'tweaked' from the PM-25 model (Franco free one).  Used a combination of Franco and CNC4XR7 X, Y, and Z mounts.


----------



## jimrk

No need for the quill DRO so used the space for PDB switch and encoder connection.


----------



## jimrk

Have the spindle controlled from a KBSI-240 (the very left) connected to the Acorn board.




removed the pot along with the E-stop.





check it out


----------



## mrosso

jimrk said:


> Have the spindle controlled from a KBSI-240 (the very left) connected to the Acorn board.
> View attachment 344368
> 
> removed the pot along with the E-stop.
> View attachment 344369
> 
> 
> check it out


Congrats on getting the spindle speed worked out. Is your solution similar to what Franco did? How did you hook up the relays to switch on/off or fwd/rev? Also, it looks like you have an AC line filter in your cabinet. Do you stick that on the very front end of the AC coming into the box? I've seen those on VFDs before, but I didn't realize we should also include them in a non-VFD setup. Thanks for posting.


----------



## jimrk

yes to what Franco showed.  You can download his diagram from his drop box.  Just has 3 wires from Acorn relay board and the 2 from the KB board going to the PM control board.  PM now has a board listed to do the same but who knows when it will ship. 
I used the filter on my G0602 VFD so just added it here just because  And I think Clearpath suggested it for their power supply.


----------



## AlanB

I checked on the current schedule for the PM CNC upgrade kit, they indicated they should have them by about Christmas. I need to dust off my LinuxCNC parts and start getting ready..


----------



## koenbro

jimrk said:


> Have the spindle controlled from a KBSI-240 (the very left) connected to the Acorn board.[...]



@jimrk  Following your conversion with great interest, as I have an order on a PM-728 with the PM CNC conversion kit and hope to see it delivered within a month. I bought an Acorn and am considering ClearPath servos (as DMM) and am struggling in choosing the specific motors. Saw in your earlier post that you went with the  CPM-SDSK-3432S-RLN for the z Axis. Are you satisfied with its performance? Do you have any recs for NEMA 23 (the PM conversion kit requires NEMA 23 for the x and y axes) with sufficient torque to mill steel?


----------



## jimrk

Very happy with the Z axis.  Seems to have plenty of power.  Have added weight of the PDB without any strain.  The one downside of the servo is no holding power when disabled.  I use the Z gib lock, easy to forget   Even when locked I can jog the head up and down. For the X and Y I used CPM-SDSK-2321S-RLN.  Been happy with them also. Have not done any steel but should be just fine.


----------



## koenbro

Much appreciate the reply. I was wondering about braking the z axis to prevent it crashing down. You mentioned earlier that the C86ACCP Clearpath Connector Board has a setting for hardware or software enable, and that switching it to the hardware setting solved the issue. Do I get that correctly?

I am in contact with one  of the Teknic engineers who offered to run a motor simulation of the PM728 to find the optimal servos, but he needs input parameters, some of which I cannot provide (have no clue on how to even get a range of reasonable upper/lower bounds), such as speed and acceleration requirements) for *worst case moving load weight* on each axis. 

I am perfectly happy to order the servos that you and other users have found to be satisfactory, and I am confident that they will get me within 80% of what I need; meanwhile  the extra info needed to refine this to 90-95% may be unavailable. So life is imperfect and decisions sometimes have to made with incomplete information, and I am comfortable with that. Before I pull the trigger,  was wondering if you or anyone else can provide these estimates? If not, I'll just go forward and order the motors you specified (and the C86ACCP board).


----------



## jimrk

Setting the C86ACCP does the job for when e-stop or if there is a servo fault.  Of course when the power is turned off the head needs to be locked or a support needs to be used.

Not sure if I can give them any helpful info.  I don't know if the tuning software saves any info that would help.  You could ask them.


----------



## koenbro

jimrk said:


> Setting the C86ACCP does the job for when e-stop or if there is a servo fault.  Of course when the power is turned off the head needs to be locked or a support needs to be used.



That is helpful, so I went ahead and ordered the C86ACCP. Meanwhile on the other discussion, I am talking to the Teknic engineer I mentioned. I am closing in on the servo choices.


----------



## kiloseven

koenbro said:


> @jimrk  Following your conversion with great interest, as I have an order on a PM-728 with the PM CNC conversion kit and hope to see it delivered within a month. I bought an Acorn and am considering ClearPath servos (as DMM) and am struggling in choosing the specific motors. Saw in your earlier post that you went with the  CPM-SDSK-3432S-RLN for the z Axis. Are you satisfied with its performance? Do you have any recs for NEMA 23 (the PM conversion kit requires NEMA 23 for the x and y axes) with sufficient torque to mill steel?


Hi koenbro,
  I used NEMA 34 sdks-3421's for the x and y axis . I use one separate IPC-5 for the Z ( CPM-SDSK-3432S-RLN). and a (CPM-SDSK-2321-ELN) for the A axis. The A axis is nema 23 clear path. And a separate IPC-5 for the X and Y axis's. The performance with The Acorn board is Very good. The mill is never lacking for power. I have the Nema 34 mount fusion files if you would like them. I would be easy to mount Nema 34's to the X and Y. Albeit it cost more now , I justified  the cost based on performance needed for heavier cuts. Faster material removal. I use the CPM-SDSK-2321-ELN
on the 8K SouthBend Lathe with the Centroid Acorn Control. Very accurate and consistent. Let me know if you would like the Fusion 360 file for Nema 34 mounts . I built the the kit my self using 20mm double ball screws and 7075 T6 for all mounting. Seems to be very robust for a Small  mill like the PM728VT.


----------



## jimrk

kiloseven said:


> Hi koenbro,
> I used NEMA 34 sdks-3421's for the x and y axis . I use one separate IPC-5 for the Z ( CPM-SDSK-3432S-RLN). and a (CPM-SDSK-2321-ELN) for the A axis. The A axis is nema 23 clear path. And a separate IPC-5 for the X and Y axis's. The performance with The Acorn board is Very good. The mill is never lacking for power. I have the Nema 34 mount fusion files if you would like them. I would be easy to mount Nema 34's to the X and Y. Albeit it cost more now , I justified  the cost based on performance needed for heavier cuts. Faster material removal. I use the CPM-SDSK-2321-ELN
> on the 8K SouthBend Lathe with the Centroid Acorn Control. Very accurate and consistent. Let me know if you would like the Fusion 360 file for Nema 34 mounts . I built the the kit my self using 20mm double ball screws and 7075 T6 for all mounting. Seems to be very robust for a Small  mill like the PM728VT.


I would be interested to see what your mounts look like compared to mine.  I like that you used 20mm screws also.  Did you do your own X ball screw mount or do like I did?


----------



## kiloseven

jimrk said:


> I would be interested to see what your mounts look like compared to mine.  I like that you used 20mm screws also.  Did you do your own X ball screw mount or do like I did?


Firstly this is the Nema 34 mount link https://a360.co/3p8Uawr  .This could be an adapter to a Nema 23 mount.  The mount than I used was much thicker than the  mount in the link.  I did build my own mount. basically just like the original lead screw mount only Thicker with a stand off to the the nema 34 mount . I won't be sharing this drawing due to lack of sales that may incur .  . It works so far. Drawings may follow. Have fun.


----------



## koenbro

kiloseven said:


> Firstly this is the Nema 34 mount link https://a360.co/3p8Uawr .This could be an adapter to a Nema 23 mount. The mount than I used was much thicker than the mount in the link. I did build my own mount. basically just like the original lead screw mount only Thicker with a stand off to the the nema 34 mount . I won't be sharing this drawing due to lack of sales that may incur .  . It works so far. Drawings may follow. Have fun.



Thank you for the fusion model, I've imported it into my library. I will likely get the NEMA 23 for axes x and y because the PM conversion kit is sized for 23. However will need to lay my hands on the kit first to see if the upsizing is easy/hard/impossible.


----------



## kiloseven

Given the length of the shafts on Teknic Servos I don't see a problem in mounting and Nema 34 adapter plate to the Precision Matthews Nema 23 Mount. Adjusting the thickness of mount for proper engagement of the shaft to coupler. Not impossible , but very much do able. The Ball screws in the PM drawing appear to be double nut.  I chose double nut on all the axis .The design Precision Matthews chose for their cnc kit is all too familiar. Simple, and if I'm not mistaken not made of aluminum. Although 7075-T6 is very sturdy, which is what I used. Just to chime in a previous post, there are options for brakes on Teknic servos , Z axis would benefit . I haven't had any trouble with creep.


----------



## jimrk

kiloseven said:


> Firstly this is the Nema 34 mount link https://a360.co/3p8Uawr  .This could be an adapter to a Nema 23 mount.  The mount than I used was much thicker than the  mount in the link.  I did build my own mount. basically just like the original lead screw mount only Thicker with a stand off to the the nema 34 mount . I won't be sharing this drawing due to lack of sales that may incur .  . It works so far. Drawings may follow. Have fun.


I was asking about the ball nut mount.. as what I showed back a few pages
https://www.hobby-machinist.com/attachments/2-jpg.327843/

How do you brake the servo without any power?


----------



## kiloseven

My X axis ball nut mount is basically the same. The Servo brakes using a relay that activates when power is removed. Relay opens under power and closes the brake circuit when power is removed. In theory using the fault circuit of the servo could be used to trigger a "no holding power event"


----------



## koenbro

kiloseven said:


> The Servo brakes using a relay that activates when power is removed. Relay opens under power and closes the brake circuit when power is removed. In theory using the fault circuit of the servo could be used to trigger a "no holding power event"



Is this relay and brake built in into the servo, or is it a separate piece of hardware? Can you pls clarify and provide link to hardware if appropriate.


----------



## kiloseven

Servo , stepper brakes that I have encountered are either physical shaft brake mechanism's or Electrical braking using heat sinks . I am no expert on this subject matter . I suggest serching for servo brake. I believe DMM servos and several other's offer built in braking via controller/servo combination.


----------



## jimrk

Think I'll cheap out on a brake option.  Put a sign on the power off switch "Park the Head First"


----------



## koenbro

jimrk said:


> Think I'll cheap out on a brake option. Put a sign on the power off switch "Park the Head First"



My kind of solution. 


Sent from my iPhone using Tapatalk Pro


----------



## kiloseven

I don't have a problem with the z axis falling. Although I do remove all bits and lock the head before putting it to bed.


----------



## jimrk

mine might stay but it doesn't take much of a jar to get it to do a face plant if I forget to lock it.


----------



## AlanB

A counterweight would fix the Z from falling.


----------



## AlanB

Received email from PM that my CNC ballscrew conversion kit and 0-10V motor speed control module for the PM-728V-T have been shipped. Less than 30 pounds ship weight.


----------



## currinh

Ditto!

Hugh



AlanB said:


> Received email from PM that my CNC ballscrew conversion kit and 0-10V motor speed control module for the PM-728V-T have been shipped. Less than 30 pounds ship weight.


----------



## mrosso

currinh said:


> Ditto!
> 
> Hugh


Same here. What do you guys think about the 16mm Z axis ball screw? Do you think it's sufficient for the Z axis load?


----------



## AlanB

Shipping stalled for awhile, but it is finally moving. Should see it early next week.

Hopefully they have selected properly.  It has a 5 year warranty if I remember correctly.
This may be another reason to consider a counterweight setup.
Here's a THK guide on ball screw selection.


			https://tech.thk.com/en/products/pdf/en_b15_069.pdf


----------



## currinh

mrosso said:


> Same here. What do you guys think about the 16mm Z axis ball screw? Do you think it's sufficient for the Z axis load?


My conversion kit showed up late last night, but haven't had time to open it yet. Waiting for the shed to warm up.

The analysis Alan pointed to looks complete. There are a lot of factors going into "is 16mm large enough". As in most design many of the factors are fuzzy. For my one off designs the cost (time) in doing these calcs is more than the cost ($) of going up a size. So, if I did the conversion myself I'd go with a larger ball screw (if it fits). Is it needed? I dunno. But, PM took enough time releasing the kit that they could/should have done these calcs (and tested, and tested, and...). For a production design I'd be surprised if they didn't. Thus, I'll assume their kit (with 16mm Z ball screw) is OK until it gives trouble.

Exciting times. Stay safe and healthy.

Hugh


----------



## jimrk

currinh said:


> My conversion kit showed up late last night, but haven't had time to open it yet. Waiting for the shed to warm up.
> 
> The analysis Alan pointed to looks complete. There are a lot of factors going into "is 16mm large enough". As in most design many of the factors are fuzzy. For my one off designs the cost (time) in doing these calcs is more than the cost ($) of going up a size. So, if I did the conversion myself I'd go with a larger ball screw (if it fits). Is it needed? I dunno. But, PM took enough time releasing the kit that they could/should have done these calcs (and tested, and tested, and...). For a production design I'd be surprised if they didn't. Thus, I'll assume their kit (with 16mm Z ball screw) is OK until it gives trouble.
> 
> Exciting times. Stay safe and healthy.
> 
> Hugh


Probably big enough but for the 'small' increase in cost I would have thought they would have gone with 20mm. Plenty of room.


----------



## jlchapman

jimrk - Did you use the ClearPath DC Power Distribution Hub?  If so, what did you use for backup 24volts?

Also on the ClearPath servos for X and Y did you buy the Enhanced Option(Enhanced option provides position setting capability of 1/6400th of a revolution. The Regular option is 1/800th)?

New to the converting to CNC and have a million questions.

Thanks,

Jerry


----------



## jimrk

jlchapman said:


> jimrk - Did you use the ClearPath DC Power Distribution Hub?  If so, what did you use for backup 24volts?
> 
> Also on the ClearPath servos for X and Y did you buy the Enhanced Option(Enhanced option provides position setting capability of 1/6400th of a revolution. The Regular option is 1/800th)?
> 
> New to the converting to CNC and have a million questions.
> 
> Thanks,
> 
> Jerry


Yes to the Hub. You do need 24v to power the Hub (not backup).  I have other power supplies for 5, 12, and 24. 
I did not opt for the Enhanced servos (might be worth the $ but I didn't think I will need it)  With what you will be spending I guess a little more might be the 'smart' thing to do.

Have fun


----------



## jlchapman

Thanks jimrk!

Well I'm just starting down the spendy and exciting road to a CNC mill.  

Deposit on PM-728VT, should be Feb/Mar.  Bought the PM-CNC conversion kit and 0-10v speed controller. Those two pieces should be here Thursday.

I did purchase the Acorn kit and the Pro Mill software from Centroid.

I placed all my components in the Shopping cart at Technik.  That was spendy, but good stuff.  Still have to pull the trigger there.

Now comes the computer and Touch screen monitor.  Anybody have some good recommendations that they are using?  Anybody using a laptop with Touch Screen?  I see B&H has an Asus 21.5 touch screen for $199.  I see you can still buy an Intel Nuc.  I'm sure there has to be some small desktops that could do the job.

What are the models of PC/monitor from Dell that Centroid sales?

I may just have to look at specs and make a purchase.

Thanks,

Jerry


----------



## AlanB




----------



## jimrk

I have a few Lenovo ThinkCentre M92p Tiny machines.  One on the lathe and one on the mill.  Seem to work fine. Did upgrade one to a SSD.  Have not pushed them so not sure if needed.  The lathe has a touch screen (ebay) and the mill is a monitor I had just sitting around.  I have both the lathe and mill next to each other so should be able to share both PC and monitor (just switch the ethernet cable and config swap but have not done that)  Need heat in my shop to get things going


----------



## ChrisAttebery

I bought a NUC with an i5-8260U cpu, 16GB ram, 256GB SSD. It was a $1k PC that was half off for Black Friday. I'm sure there are cheaper options. I wanted something with as much power as possible to run Fusion360.

If you look on Centroid's web site they list the minimum specs for the PC. 

Also, if you buy a NUC there's a VESA mounting bracket you can buy that will allow it to be bolted to the back of the monitor. It was like $13 on Amazon.


----------



## koenbro

I got this Nuc:

Intel NUC 8i7BEK Mini Desktop, Intel Quad-Core i7-8559U Upto 4.5GHz, 16GB RAM, 512GB SSD, HDMI, Thunderbolt 3, Card Reader, Wi-Fi, Bluetooth, Windows 10 Pro

Can run Fusion, Centroid Mill Pro, SheetCam. 

Sent from my iPhone using Tapatalk Pro


----------



## jlchapman

Thanks for the responses!

I think I'm going with Koenbro NUC.  It has the Intel Iris plus 655 graphics.  I dont know for sure how much difference the Intel Iris makes, but Koenbro replied that he is running Fusion, Centroid Mill Pro and Sheetcam.  Sounds good to me.

I also like Chris mentioning the VESA bracket.

Jerry


----------



## koenbro

Yes it does run Fusion, Centroid Mill Pro, Mach4 (for the Avid CNCRouterParts plasma table), and Sheetcam, and usually have several of them open. For example when I cut with the plasma, I use Fusion > Sheetcam > Mach4. It does have the Vesa hole pattern on the back as does hte monitor, but I mount them offset. The monitor, btw is the Planar Helium PCT2235 Touch Screen 22" LED LCD Full HD Resolution Monitor with Helium Stand


----------



## jlchapman

Nice clean and compact setup on the monitor.  What is the Raspberry Pi for?


----------



## koenbro

I wanted to use it for an Arduino project (with motor drivers for some NEMA17s) but have abandoned that project and that pi is repurposed for photo/video backup storage now.  I will remove it from the workstation above and put a DIN rail in its place, onto which will go a PS and an ethernet switch as part of my PM 728 CNC conversion.

One of the disadvantages of the NUC is that it only has one ethernet port, and I need to drive two separate CNCs, one w/ Acorn the second with ESS/Mach4. I will use the switch to not have to swap cables out.


----------



## jlchapman

SimplyNUC has a lid for $39 that adds another RJ45 and USB port.  I dont know if this would work with your NUC, but its worth checking out.









						NUC Gen 8 RJ45 and USB Lid - Simply NUC
					

. .




					simplynuc.com


----------



## mrosso

anyone know of a way to adapt a 3/8 in shaft servo motor to the 8mm coupler? Same with a .5 in servo to the 14mm coupler in the Precision Matthews CNC kit.


----------



## jimrk

what are the shaft sizes on the screws?  Might need to search a bit but lots of options.

I like this style
Shaft Encoder Connect D34 L45 Double diaphragm 5mm-14mm alloy Flexible Coupling | eBay


----------



## mrosso

jimrk said:


> what are the shaft sizes on the screws?  Might need to search a bit but lots of options.
> 
> I like this style
> Shaft Encoder Connect D34 L45 Double diaphragm 5mm-14mm alloy Flexible Coupling | eBay


Thanks lmrk. The PM-728vt CNC kit shipped by Precision Matthews has 10mm ball screw shafts on x, y and z. The motor-ends of the couplers that came with the kit are 8mm for x and y and 14mm for z. I'm using ClearPath servos, and they are .375 in shafts for x and y and .5 in for z.


----------



## jimrk

mrosso said:


> Thanks lmrk. The PM-728vt CNC kit shipped by Precision Matthews has 10mm ball screw shafts on x, y and z. The motor-ends of the couplers that came with the kit are 8mm for x and y and 14mm for z. I'm using ClearPath servos, and they are .375 in shafts for x and y and .5 in for z.


search for couplers 
10 x 9.52
this is a style
3/8" x 10mm Flexible Jaw Spider Shaft Coupling CNC Stepper Motor Rare Coupler | eBay

10 x 12.7


from the above link you can get the 10x12.7


----------



## jimrk

BTW, you might need to go with the same style as PM sent so they will fit with the mounts.  I was able the make the mounts fit with the couplers


----------



## AlanB

mrosso said:


> anyone know of a way to adapt a 3/8 in shaft servo motor to the 8mm coupler? Same with a .5 in servo to the 14mm coupler in the Precision Matthews CNC kit.


With those couplers each half can be selected for different shaft size, as I understand it. So you can just replace the motor halves.


----------



## jlchapman

Take a look at these.  Clough42 on YouTube uses these.

For whatever reason the URL doesnt work.  Goto McMasterCarr and search for 'Clamping High-Parallel-Misalignment Flexible Shaft Couplings'


----------



## mrosso

Thanks for all the tips, guys!


----------



## jlchapman

Look what showed up on my Doorstep today!


----------



## jlchapman

Where do I find the file for the 3D printed din bracket for the IPC-5?


----------



## jlchapman

I know you can connect the Clearpath servos directly using drawing S14972 from Centroid.  Is it worth implementing the C86ACCP board into my CNC project?  The cost is not much.  What would I be missing if I dont use it?  Status LED for faults.  Give me some reasons to use it.

Thanks


----------



## jimrk

jlchapman said:


> Where do I find the file for the 3D printed din bracket for the IPC-5?


I don't recall if I made one or not, I'll check when it get light and warmer out.  You can check the manual online for dimensions.


----------



## jimrk

jlchapman said:


> I know you can connect the Clearpath servos directly using drawing S14972 from Centroid.  Is it worth implementing the C86ACCP board into my CNC project?  The cost is not much.  What would I be missing if I dont use it?  Status LED for faults.  Give me some reasons to use it.
> 
> Thanks


I liked the fact you can use the clearpath cables (I did build your own molex cables for inside my control box)  I didn't cut any of the clearpath cables.
The fault feature seems to work well.  full stop when you crash  
Have you watched the youtube vids?


----------



## jlchapman

jimrk said:


> I liked the fact you can use the clearpath cables (I did build your own molex cables for inside my control box)  I didn't cut any of the clearpath cables.
> The fault feature seems to work well.  full stop when you crash
> Have you watched the youtube vids?


Thanks jimrk.  I liked the feature of using uncut clearpath cables and the status led for faults.  I was going to use Centroids cable management for getting the cables into the enclosure.

Can you be more specific on the youtube vids? or maybe url links?

Thanks.


----------



## jimrk

jlchapman said:


> Thanks jimrk.  I liked the feature of using uncut clearpath cables and the status led for faults.  I was going to use Centroids cable management for getting the cables into the enclosure.
> 
> Can you be more specific on the youtube vids? or maybe url links?
> 
> Thanks.


just search youtube for C86ACCP 

(220) Clearpath Servos on Centroid ACORN Control using the C86ACCP - YouTube

I printed a bulkhead for molex connectors.. could be better but works 'ok'


----------



## jimrk

jimrk said:


> I don't recall if I made one or not, I'll check when it get light and warmer out.  You can check the manual online for dimensions.
> 
> View attachment 351506


I did not do a DIN
This 'should' work


----------



## jlchapman

Thanks jimrk for the braket file.  Bracket printed fine and mounts to the din rail.  Hopefully I have an IPC-5 this week.  Having that printed I can almost layout where everything goes in the enclosure.  Then I'll order an enclosure.


----------



## jimrk

jlchapman said:


> Thanks jimrk for the braket file.  Bracket printed fine and mounts to the din rail.  Hopefully I have an IPC-5 this week.  Having that printed I can almost layout where everything goes in the enclosure.  Then I'll order an enclosure.


Glad to hear.  After doing it I got to thinking about heat.  I don't think it should be a problem with it vented to the sides.  I can put some holes in if you want.  Let me know after you get the IPC-5. I used the mounting holes used in the manual so hope they are correct.


----------



## jlchapman

Got my NUC yesterday.  Its all setup.  I had to reload to get rid of Microsoft online login crap.  Did the Centroid Bench test and CNC12 install. Everything is great.  Clearpath package will be here Friday.

I know Fusion 360 well enough to design components.  What I dont know is how to use Centroid's processor in Fusion 360.  I really dont know much about selecting tools, Setup to create NC, etc.  Really not much about the CNC portion of Fusion 360.

So what I was able to do poorly is the following:  created a 3d model, square with 5 hole bolt pattern.  Selected manufacture, did post configuration using Centroid, picked a random end mill, did a simulation.  It was crude but a good start.  Was very cool to watch.

Any suggestions on good videos to refine my adventure into the CNC process?


----------



## jimrk

jlchapman said:


> Got my NUC yesterday.  Its all setup.  I had to reload to get rid of Microsoft online login crap.  Did the Centroid Bench test and CNC12 install. Everything is great.  Clearpath package will be here Friday.
> 
> I know Fusion 360 well enough to design components.  What I dont know is how to use Centroid's processor in Fusion 360.  I really dont know much about selecting tools, Setup to create NC, etc.  Really not much about the CNC portion of Fusion 360.
> 
> So what I was able to do poorly is the following:  created a 3d model, square with 5 hole bolt pattern.  Selected manufacture, did post configuration using Centroid, picked a random end mill, did a simulation.  It was crude but a good start.  Was very cool to watch.
> 
> Any suggestions on good videos to refine my adventure into the CNC process?


lots out there but I like Lars for both CAD and CAM
(230) Lars Christensen - YouTube

Martycncgarage is good for setup (230) martyscncgarage - YouTube

NYCNC also  (230) NYC CNC - YouTube


----------



## Genghis6400

Greeting all from the NYC!! Hoping everyone  is doing well. I’m just a beg beginner enthusiast, just ordered a 728-VT Dec and is waiting on the delivery


----------



## Genghis6400

Seeking recommendation.... While I’m waiting for the delivery of the 728, I’m contemplating on whether to build a table for the 728 or getting the manufactured stand. If anyone had any experience with this situation please kindly point a fella in the right direction. Greatly appreciate on all opinions


----------



## rwm

I built a stand. Mainly because of space issues I wanted a chest of drawers under the machine. It is not optimal. If you have the space, go with the factory stand. It does have some storage.
Robert


----------



## Badabinski

I'm in the same boat as you. I went for the factory stand after having my last mill mounted on a bench and suffering from quite a bit of vibration. I have to admit, I'm going a bit crazy waiting for the mill to ship! I can't wait to make some chips and I keep buying tooling and stock in anticipation.


----------



## Genghis6400

rwm said:


> I built a stand. Mainly because of space issues I wanted a chest of drawers under the machine. It is not optimal. If you have the space, go with the factory stand. It does have some storage.
> Robert


My main concern is the stability of the factory stand. I have tile flooring and will not be able to drill and mount the stand like the OP where they can drill into the cement.


----------



## Genghis6400

Badabinski said:


> I'm in the same boat as you. I went for the factory stand after having my last mill mounted on a bench and suffering from quite a bit of vibration. I have to admit, I'm going a bit crazy waiting for the mill to ship! I can't wait to make some chips and I keep buying tooling and stock in anticipation.


Matt at PM said that delivery would be from  mid to late January..... so it could be any day now. Did you order any accessories with the machine? If you did, they would have to wait till all are available before they ship it out to you.


----------



## Badabinski

Genghis6400 said:


> Matt at PM said that delivery would be from  mid to late January..... so it could be any day now. Did you order any accessories with the machine? If you did, they would have to wait till all are available before they ship it out to you.


I did. I'm guessing I'll probably be waiting on the clamping kit and vise, since those are both showing as available on backorder. I wonder if I could just pay to have those shipped separately so I could get the machine sooner. Definitely champing at the bit here!


----------



## Genghis6400

Badabinski said:


> I did. I'm guessing I'll probably be waiting on the clamping kit and vise, since those are both showing as available on backorder. I wonder if I could just pay to have those shipped separately so I could get the machine sooner. Definitely champing at the bit here!


     I'm sure that a possibility that they can accommodate for you.... However if you ordered your with the DRO like me you would have to wait till they install the DRO before shipping it out.
     Will you be using the R8 collet system or adapt to the Tormach TTS system. I myself is thinking the Tormach TTS.


----------



## SRay53TxTn

I have one on order since early December w/DRO and feel your chomp.
I heard many orders and builds are in process, depends on place in line, and the PM staff are very happy and busy. Seems the PM728 is a huge hit.


----------



## Badabinski

Genghis6400 said:


> I'm sure that a possibility that they can accommodate for you.... However if you ordered your with the DRO like me you would have to wait till they install the DRO before shipping it out.
> Will you be using the R8 collet system or adapt to the Tormach TTS system. I myself is thinking the Tormach TTS.


I ordered a DRO as well, so my hope has been that the vise and clamping kit will come in before the machine is ready to go. Keeping my fingers crossed!

I'll probably stick with R8 collets for now because I like how low-profile they are. I'm planning on doing some work that may stretch the Z height available, so I'll need every inch I can get. A lot of my workholding accessories are also quite oversized for the machine, so I need to save Z height to accommodate that (e.g. sine table, dividing head). I've been eyeing a spindle lock from Priest Tools as a way to make tool changes easier to make up for it.

I'll definitely have some stock to play with once it gets here, although I've exhausted my fun budget for the next few months...


----------



## SRay53TxTn

Nice plate of metal for the 728. This hobby sure expands the mind in project opportunities.


----------



## Genghis6400

Badabinski said:


> I ordered a DRO as well, so my hope has been that the vise and clamping kit will come in before the machine is ready to go. Keeping my fingers crossed!
> 
> I'll probably stick with R8 collets for now because I like how low-profile they are. I'm planning on doing some work that may stretch the Z height available, so I'll need every inch I can get. A lot of my workholding accessories are also quite oversized for the machine, so I need to save Z height to accommodate that (e.g. sine table, dividing head). I've been eyeing a spindle lock from Priest Tools as a way to make tool changes easier to make up for it.
> 
> I'll definitely have some stock to play with once it gets here, although I've exhausted my fun budget for the next few months...


Definitely we are on the same boat with the DRO, Vise, Collets etc etc... happy waiting!!! So it look like I will be getting the factory stand with 728. I am also think of all tree of the Priest Tools Spindle Lock, Spindle Stop and the Power Lift!!!! buy more than two items you 10 percent off!! BTW where did you get your stocks from?


----------



## Badabinski

Genghis6400 said:


> Definitely we are on the same boat with the DRO, Vise, Collets etc etc... happy waiting!!! So it look like I will be getting the factory stand with 728. I am also think of all tree of the Priest Tools Spindle Lock, Spindle Stop and the Power Lift!!!! buy more than two items you 10 percent off!! BTW where did you get your stocks from?


Ahh, I'm quite jealous. I'd love to get all three at some point.

I got my stock from a local industrial surplus store in Utah. Lots of offcuts of all kinds (mostly steel and stainless), including some Invar 36 that was there this last time. I buy most of my large stock from there and just buy the small stuff from places like McMaster. Steel is $.50 a pound, so it definitely helps make big projects more feasible! There are probably similar places in your neck of the woods.


----------



## jlchapman

Badabinski said:


> Ahh, I'm quite jealous. I'd love to get all three at some point.
> 
> I got my stock from a local industrial surplus store in Utah. Lots of offcuts of all kinds (mostly steel and stainless), including some Invar 36 that was there this last time. I buy most of my large stock from there and just buy the small stuff from places like McMaster. Steel is $.50 a pound, so it definitely helps make big projects more feasible! There are probably similar places in your neck of the woods.


What is the name of the Industrial surplus store?  Might be worth driving 55 miles.


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## Badabinski

jlchapman said:


> What is the name of the Industrial surplus store?  Might be worth driving 55 miles.


Hey fellow Utahn! It's called NPS Industrial. I think there might be a location in Orem, but I go to the Salt Lake one. Their stock is pretty variable, but apparently it's been quite good recently. It's also a pretty good place to get weird taps (especially spiral fluted ones) for a decent price. Best to bring good gloves with you, because everything is kind of filthy and the metal often has sharp burrs from saw cuts.

Edit: the Orem location probably doesn't have metal. It definitely appears a lot less "industrial."


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## jlchapman

Badabinski said:


> Hey fellow Utahn! It's called NPS Industrial. I think there might be a location in Orem, but I go to the Salt Lake one. Their stock is pretty variable, but apparently it's been quite good recently. It's also a pretty good place to get weird taps (especially spiral fluted ones) for a decent price. Best to bring good gloves with you, because everything is kind of filthy and the metal often has sharp burrs from saw cuts.
> 
> Edit: the Orem location probably doesn't have metal. It definitely appears a lot less "industrial."


Thanks Badabinski!  I'll have to stop there the next time I head north.  I'll check out the Orem location just in case they do carry metal.


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## nobog

Just received my PM728 a week ago.  I had a stand so I re-used that.  Got the power feed also but not shown in the pic.  Very quiet, smooth X,Y, & Z.  Its a very nice machine.


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## jlchapman

nobog said:


> Just received my PM728 a week ago.  I had a stand so I re-used that.  Got the power feed also but not shown in the pic.  Very quiet, smooth X,Y, & Z.  Its a very nice machine.


Nice,  When did you order it?


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## nobog

It was nearly a 3 month wait.


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## SRay53TxTn

Officially jealous.
Waiting for mine.
nobog, Where did you get the mill vise speed handle?


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## jlchapman

SRay53TxTn said:


> Officially jealous.
> Waiting for mine.


I'm waiting also, but I didn't order until the first of this month.  Guess I can count on at least 2-3 months.  I only ordered the 728 no accessories.


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## nobog

The speed handles are all over ebay, but you need to match it to the vise which I got:
4" 440V CNC Milling Machine Vise 0.0004" - Vise - Workholding - Products (shars.com)

This thing is cooler than the mill, its like owning a giant gage block!


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## SRay53TxTn

nobog said:


> The speed handles are all over ebay, but you need to match it to the vise which I got:
> 4" 440V CNC Milling Machine Vise 0.0004" - Vise - Workholding - Products (shars.com)
> 
> This thing is cooler than the mill, its like owning a giant gage block!


I have the same vise. It's just waiting for my 728 mill to set it on.



Thank for the info on the speed handle & have fun with the 728.


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## nobog

Yep, that's the one!  I had mine also before I had the mill.  4" is the perfect size.
I upgraded from a Sieg SX3 for the PM 728.


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## AlanB

The mills come in batches. So the wait times won't necessarily be the same, it depends when a batch comes in and where in the que the order is, plus the delays to install options.


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## nobog

The Tagara vice is nice and it comes with the alignment "pins" on the bottom but the pins are about 0.500" and the slots on the mill are 0.470" (or something close) so I thought I would mill to size but they are hardened - FYI.  As far as the speed handle, if I remember correctly you need a 9/16" hex - most of the listings on ebay are for 5/8" - again verify before ordering - as the 5/8" is used on the more common 6" vises.


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## SRay53TxTn

Thanks for that update!

*Just received notification that my PM-728 /DRO has been completed and shipped.*

Freight company just called and I'm setup for a delivery this Thursday. Kid at Christmas excitement level - my first mill.


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## jlchapman

AlanB said:


> I've wanted to get a small mill for many years, initially I planned on a Grizzly G0704, then changed to a PM25 and considered many others along the way. But the procurement just kept slipping further and further out. I've been "getting by" with a Grizzly G0516 which is a combo 10x21 lathe and Mini Mill which I've had since 2003. The lathe is pretty capable but the Mini Mill is very limiting and the lathe cross slide is rather small and strange for a mill table. I'd like to get a better lathe, but I need the mill too so I really need to upgrade the mill first. Then maybe I'll be looking at lathes...
> 
> Recently I decided to just get on with ordering something, and was preparing to order a PM25 when the PM728 popped up. I waited and waited to see them in the field, but nothing was showing up, so finally I bit the bullet and made the order.
> 
> A few days before Christmas I got the tracking email and Saia LTL Freight had the package. There were a lot of tracking updates until it departed Chicago late in the week before Christmas, then all updates stopped. There were no estimates of delivery, no updates on where it was, just silence.
> 
> The day after Christmas my wife took the call saying it would be at the terminal in a day or two. Still no tracking updates, no estimates online. It hit the terminal early Friday morning and suddenly there were tracking updates online.
> 
> I had requested "hold at terminal", as I had done with the lathe years ago, as it works out better for me. We are on a cul-de-sac and big trucks are not happy delivering here, and my long sloping driveway is not fun to deal with. So I take a small flatbed trailer to the depot, they forklift the crate onto it, and I back it up wherever I want it.  The trailer is much lower than my truck bed, and can be tilted if that is needed.
> 
> I made the trek to the Saia depot Friday afternoon and the very helpful people at the depot forked the crate on the pallet onto my trailer. They helped me remove the shipping pallet from under the crate, and I strapped it down thoroughly for the ride home. I screwed some 2x4's to the trailer bed in front to insure it would not slide forward during hard braking. I brought new straps and cranked them down till the crate was complaining so it would not be passing me on the freeway.
> 
> View attachment 309153
> 
> 
> I used a hydraulic lift table to bring the mill from the trailer into the garage and up to workbench height and slide it onto a polyethylene cutting board which I can move easily. All the moving effort has been easy for two adults, no heavy lifting, just sliding an inch or so at a time. The cutting board wants to slide on the bench so I had to keep moving it back under the mill as we progressed. In summary the hydraulic lift table cart was excellent and made the job easy. A shop crane wasn't practical due to the gradient of the driveway and the low clearance under the workbench.
> 
> 
> View attachment 309154
> 
> 
> Then I built a temporary gantry and used a hydraulic jack and some threaded rods to lift it and position the drip tray underneath, an easy one man job. Here it has just landed:
> 
> View attachment 309155
> 
> 
> So now it is in position on the mobile workbench with plenty of drawers to contain the tooling:
> 
> View attachment 309156
> 
> 
> My plans are to use it manually for awhile as I prepare to convert it to CNC. This conversion is not going to be easy as there are no CNC kits available for the new mill. I may do a bootstrap conversion, making 3D printed parts and later converting to machined parts. I have been collecting a lot of the CNC controls parts for awhile so I have a Linux CNC system and Mesa boards as well as closed loop stepper motors and electronics in boxes. I've been doing 3D design and printing for a couple of years but this will be my first CNC conversion, which I've been reading about for years.
> 
> So it begins!


Alanb What toolbox/bench is your 728 sitting on?


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## AlanB

It's a Home Depot Husky 61 inch 10 drawer mobile work center with flip-up pegboard and shelf, however the pegboard is not flipped up and will be removed later. It has six heavy duty wheels.


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## Genghis6400

Spoke to personnel at PM regarding 728 stand and they said that Its back order til march.


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## jlchapman

Thanks AlanB for the workbench information.


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## Badabinski

I sent a quick email to PM today and it sounds like my mill should (hopefully!) be ready to ship by the end of the week. The vise is still in transit to their warehouse, but it sounds like I can pay to have that shipped separately if it's not there by the time the mill is ready to go. The shipping situation isn't their fault, so I don't mind paying so I can get my mill sooner. The bit I was champing at is sawdust at this point!


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## SRay53TxTn

I don't have a large shop area, however this setup works well for my limited space 1/2 of a double car garage, wife has her car on the other side.
My  PM728 arrived on Thursday afternoon and I spent most of my time the last couple days unwrapping, setting it up for mounting on the stand, and checking function and operation. It seems like an excellent quality mill. 
Finding that what others have said is true - tools are expensive and you are always looking for more/better to improve your skill level.

I really enjoy spending my retirement time in my little hobby shop area - my zen.


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## Genghis6400

SRay53TxTn said:


> I don't have a large shop area, however this setup works well for my limited space 1/2 of a double car garage, wife has her car on the other side.
> My  PM728 arrived on Thursday afternoon and I spent most of my time the last couple days unwrapping, setting it up for mounting on the stand, and checking function and operation. It seems like an excellent quality mill.
> Finding that what others have said is true - tools are expensive and you are always looking for more/better to improve your skill level.
> 
> I really enjoy spending my retirement time in my little hobby shop area - my zen.
> View attachment 354422


That’s a really nice set up you got there!!!! Still waiting for mine to arrive however the Stand is on back order now and won’t be in stock till March. May I ask what lathe is that you have there? I’m think to get the PM1228
Dan


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## SRay53TxTn

Thanks for the kind words!
That is the PM-1228VF-LB lathe. I have had it about almost a year and it does everything I need for my retirement hobby projects. Plus it fits my work space, spend a lot of time in that area each day.


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## jlchapman

Very nice setup.  You would be surprised how much you can do in such a space.

I started 5 year ago prepping for retirement.  It seems like there is always another tool to buy.  If its not tools its material.  Great part is the hobby is very satisfying.  It amazes me what you can build in a home shop.


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## nobog

SRay, nice shop !  The only thing on the 728 that I wished they would have done was to eliminate 10' of that DRO cabling, its just sits there in a spool, can't imagine someone would want to remote mount that thing so far away.  Make the extra cable length an option.  And yes, the 728 was a retirement present to myself !


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## Badabinski

Just got my shipment notification! I ordered on 12/22. Got the mill with DRO and stand, X axis power feed, vise, and some other accessories. Sounds like a lot of the accessories are back in stock.


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## Genghis6400

Badabinski said:


> Just got my shipment notification! I ordered on 12/22. Got the mill with DRO and stand, X axis power feed, vise, and some other accessories. Sounds like a lot of the accessories are back in stock.


     So it would seems that me and you are really on the same boat!!!! Just got my notice today as well. Not too sure how to get it down the 4-5 steps down to the basement yet but I’m sure with a couple of buddies it be fine.
     Suggestions are welcome.


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## jimrk

Genghis6400 said:


> So it would seems that me and you are really on the same boat!!!! Just got my notice today as well. Not too sure how to get it down the 4-5 steps down to the basement yet but I’m sure with a couple of buddies it be fine.
> Suggestions are welcome.


Take the head and table off and will be easy.


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## Genghis6400

jimrk said:


> Take the head and table off and will be easy.


thank you for the suggestion. I ordered mine with the DRO... Would that interfere or making it more difficult to removing the table and head?


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## jimrk

Genghis6400 said:


> thank you for the suggestion. I ordered mine with the DRO... Would that interfere or making it more difficult to removing the table and head?


IDK but I would think not much.


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## SRay53TxTn

ON page 4 of manual they show head R&R. I can shoot some pics of mine w/DRO if that would help you.


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## Genghis6400

SRay53TxTn said:


> ON page 4 of manual they show head R&R. I can shoot some pics of mine w/DRO if that would help you.


super thankful for the PDF.... definitely give me a visual aid to think about. very helpful.


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## Just for fun

SRay53TxTn said:


> I don't have a large shop area, however this setup works well for my limited space 1/2 of a double car garage, wife has her car on the other side.
> My  PM728 arrived on Thursday afternoon and I spent most of my time the last couple days unwrapping, setting it up for mounting on the stand, and checking function and operation. It seems like an excellent quality mill.
> Finding that what others have said is true - tools are expensive and you are always looking for more/better to improve your skill level.
> 
> I really enjoy spending my retirement time in my little hobby shop area - my zen.
> View attachment 354422


Congratulations!  I'm going to retire in May, currently I do not own any machining equipment.  But those are the exact machines I have in mind.  I'm probably a year out at this point, I need to finish my Hot Rod project first.

Tim


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## nobog

First batch of "production" parts completed on the 728 - it works as it should.

(lawn mower repair parts I sell on eBay)


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## Tipton1965

What part of the lawn mower is that?


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## nobog

I call it Save-A-Deck, John Deere does a lot of good things but not this - the front deck hanger on some zero-turns, after 200 hours, will "saw" thru the tabs and your 3 options are to either weld something on, replace the deck ($1,000.00), or buy this !


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## Genghis6400

Hey everyone! Happy president's day!!! I'm planning on getting the Priest Tools accessories for my 728, so my question is..... Does anybody here have any experience with the Priest Tools accessories? Or have any opinions regarding this matter. Greatly appreciated


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## SRay53TxTn

I'm curious on the Priest Tools as well.


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## Genghis6400

So..... the 728 finally arrived today!!! With a couple of buddies we were able to move it to the basement. Checking all the ancillary that was purchased along with the mill. I’m just missing the Stand is all. PM said that the next batch is in March, so I got plenty of time to read the manual and prepare a good location for the mill.


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## Badabinski

My mill has arrived! I'm clocking out early today so I can finish getting the shop ready.


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## Genghis6400

Badabinski said:


> My mill has arrived! I'm clocking out early today so I can finish getting the shop ready.
> 
> 
> 
> 
> 
> 
> 
> 
> 
> View attachment 356118


Hey Buddy, Congrats!!!!! Oh man you got the Stand as well, luck you! Now all you gotta do is set up and start chipping!!!! Good luck and have fun my friend!!!


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## Badabinski

Managed to get the mill across my yard and into my shop without incident. I haven't trammed it in yet, but I fired it up and put it through the first running procedure.






One thing I noticed is that the spindle makes a weird noise and vibrates a bit when I move the quill while the mill is running. Is this normal? Or did I goof something up?


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## Genghis6400

Badabinski said:


> Managed to get the mill across my yard and into my shop without incident. I haven't trammed it in yet, but I fired it up and put it through the first running procedure.
> 
> View attachment 356331
> 
> 
> One thing I noticed is that the spindle makes a weird noise and vibrates a bit when I move the quill while the mill is running. Is this normal? Or did I goof something up?


Looks really nice! How is your spindle Fine feed? Mine got a little hiccup spot... its a kind of stiff spot at the same place for every full knob rotation. I contacted PM and was told that they'll check up with their people and would get back to me.


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## MarkZ

Genghis6400 said:


> thank you for the suggestion. I ordered mine with the DRO... Would that interfere or making it more difficult to removing the table and head?


On mine, the DRO scales and cables came attached but the display and bracket were in a separate box. You will have to exercise some extra care to avoid damage to the scales and cables but otherwise I think it shouldn't stop removal.

I turned my stairs into a ramp with a couple of 2x6's and eased the pallet down the stairs with a chain hoist so I avoided diassembly.


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## bburns0909

Genghis6400 said:


> Hey everyone! Happy president's day!!! I'm planning on getting the Priest Tools accessories for my 728, so my question is..... Does anybody here have any experience with the Priest Tools accessories? Or have any opinions regarding this matter. Greatly appreciated


I considered the Priest Tools quill stop, but I wasn't a fan how of how it appears the hard stop is attached to the machine with those two tiny little front panel screws. Maybe they will, but I'm skeptical they will hold a lot of downforce if you hit the stop hard or put any significant downforce on it. I'm currently designing/prototyping my own that uses other bolt holes in the machine. Will post a separate thread when complete.


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## Genghis6400

So the culprit for the stiff spot in the Fine Spindle Feed was a dent spot on the worm gear shaft set screw slot. Probably caused by assembly person whom was not careful and screwed the set screw off spot. The set screw pressed and gouged out that spot and caused the damage in the slot. I was able to file it down and straighten out the slot and the Fine Feed is functioning much nicer.


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## nobog

Wow, that part looks like it was machined in a first year high-school machine shop class ...


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## jlchapman

My PM728 is on its way.  Should have it by the end of next week.

I will immediately start the conversion to CNC.  I have done the bench test with Acorn.  Electrical box arrives today.  My TTS tools have arrived. Need to order some more end mills.

Pretty exciting.

Jerry


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## rwm

Another 728 issue: the upper line of my "one shot" oiler will not stay primed and leaks back to the reservoir. So to fill the line takes 5 or six pumps. So it's actually a 6 shot oiler. Does anyone else have this problem or do I have a defective oiler? 
Robert


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## bburns0909

rwm said:


> Another 728 issue: the upper line of my "one shot" oiler will not stay primed and leaks back to the reservoir. So to fill the line takes 5 or six pumps. So it's actually a 6 shot oiler. Does anyone else have this problem or do I have a defective oiler?
> Robert


I had a similar issue only to find out that I had to keep the oil filled up more. Try topping the oil off to the top of the reservoir and see if that helps. I thought my oiler was broken at first.


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## nobog

Now I can find it!

Although the mill is top-notch, the spindle wrench leaves something to be desired. Just feels cheap.  So I added some "speed holes" which helps with tool changes - it's much faster  - then a new coat of orange paint so it stands out.

JK


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## rwm

I didn't like the way the wrench worked from the side so I made this.











Robert


----------



## Badabinski

Has anyone else installed a Priest Tools spindle brake? I'm trying to figure out what I'm doing wrong when wiring the switch in. The cable that's crimped onto the switch doesn't seem long enough. The instructions mention an extension cable, but I didn't get anything like that with my spindle brake. Am I just being dumb/missing the point? Or was I supposed to get an extension cable with the spindle brake? (I know this is only tangentially related.)


----------



## jimrk

Badabinski said:


> Has anyone else installed a Priest Tools spindle brake? I'm trying to figure out what I'm doing wrong when wiring the switch in. The cable that's crimped onto the switch doesn't seem long enough. The instructions mention an extension cable, but I didn't get anything like that with my spindle brake. Am I just being dumb/missing the point? Or was I supposed to get an extension cable with the spindle brake? (I know this is only tangentially related.)


I have not but the install doc does seem to talk about an extension cable.  I would assume it ties into the cover kill switch.  If was not included give him a call.


----------



## jlchapman

Looks like your missing the extension cable from Priest.

Let us know how you like it when it up and running.

Jerry


----------



## jlchapman

jimrk said:


> Find a belt that will work and then cut the front part off and make it pretty
> 
> View attachment 340192


Jim,
Could I get your Fustion360 files for the encoder and the spindle pulleys?  It sure would save me some time.

Thanks,

Jerry


----------



## jimrk

jlchapman said:


> Jim,
> Could I get your Fustion360 files for the encoder and the spindle pulleys?  It sure would save me some time.
> 
> Thanks,
> 
> Jerry


Sure, I'll just have to find them.


----------



## Genghis6400

SRay53TxTn said:


> Thanks for the kind words!
> That is the PM-1228VF-LB lathe. I have had it about almost a year and it does everything I need for my retirement hobby projects. Plus it fits my work space, spend a lot of time in that area each day.


I ended up getting the 1340GT


----------



## sakumar

jimrk said:


> Setting the C86ACCP does the job for when e-stop or if there is a servo fault.  Of course when the power is turned off the head needs to be locked or a support needs to be used.
> 
> Not sure if I can give them any helpful info.  I don't know if the tuning software saves any info that would help.  You could ask them.


I asked this question on the Centroid Acorn forum as well -- If there is a servo fault, how can I stop the spindle's DC motor? Is there a way to use the Relay OUT1 signal from Acorn to achieve this?

I already have an E-stop configured which stops both the spindle and also disconnects Acorn's E-Stop input 8 from COM. This effectively stops all the motors. To stop the spindle I use a contactor. I also have a Z-axis lock which is triggered by the Acorn during E-stop to prevent this z-axis from slipping down.

However, if there is a servo fault, I'm not sure how I can stop the spindle. Thanks for any help/pointers.

Also, I should mention that at this time I don't plan to use the Acorn's VFD features to control the 727VT's brushless DC spindle hence the need for an external mechanism to stop the spindle in case of a servo fault.


----------

