# PM-833TV CNC conversion kit availability?



## BehemothTheCat (Feb 11, 2022)

Gentlemen,

I'm looking for a source of a CNC conversion kit for PM-833TV other than Heavy Metal CNC. I couldn't find any other kits myself and doubt they exist, but figured it wouldn't hurt to ask.

I ordered a PM-833TV for the sole purpose of converting it to CNC and got it delivered mid-December. I got in touch with Heavy Metal CNC in early January and was corresponding with a gentleman by the name of Jose, who was using Bruce Nelson's e-mail address. I was unaware at that point that Bruce had passed and assumed it was one of his employees. I placed an order for their premium kit in mid-January and patiently waited. By the end of the month I emailed them to check on the status, but received no reply. I then proceeded to text and call, all to no avail. Their website had been up until early this week, but thankfully somebody has taken it down now.

By the looks of it Heavy Metal CNC is no more and my order will never be delivered. I'm not sure what to do. I don't think I'm up to improvising a mounting kit myself, so it boils down to waiting for somebody to develop one or selling the mill. 

Thanks!

Matt


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## joeblow65 (Feb 11, 2022)

That's rough man. I knew Bruce had passed but I didn't think the company would end. I guess it was more of a hobby/passion project for him specifically. For what its worth I have had to heavily modify most of my parts in the kit that I got from them due to changes in the castings so im really ending up modifying the parts to get it working and making my own parts. Only advice I can really give is if none of your calls or emails are being answered is to start a charge back process through paypal or your CC company, those kits aren't cheap and I couldn't let that much money float off into the sunset. 

Once I'm done modifying parts I would be happy to put up the drawings for the parts I've had to redesign. you could always use the acme screws on the machine and mount motors to them so you can make all the parts you need for a final conversion.


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## 7milesup (Feb 11, 2022)

I too am seriously considering converting my mill.  Unfortunately I have just the 833T and not the TV so having gears is an issue IMHO.  I thought about changing the spindle out, but unclear how big of a project that will be. My existing spindle is now leaking (with not much use) so I feel like I am getting to a crossroads.  
I always felt that the Heavy Metal kit was too spendy for what you received.


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## BehemothTheCat (Feb 11, 2022)

Thank you for replying. I didn't realize the castings had changed so much. I would certainly appreciate the drawings once you're done with your conversion. I don't have access to any other mill, but thankfully I haven't disassembled the 833, so I might be able to use it to modify/make the parts.

Yes, ~$1,250 shipped is quite a bit, but if you consider the cost of the ball screws, I doubt I'd be able save much even if I could somehow improvise the mounts etc. I ended up filing a PP claim today as I figured it was pretty much hopeless. Within minutes Jose replied to my original message from almost two weeks back:


> Sorry for the inconvenience. But I thought I’d ask again to see if you still want the kit I can ship it today which is Friday. My business partner had passed away in December and we’re still trying to get everything organized but I can have it ship by Friday if that’s OK or else I can reimburse you if that’s what you want thank you. Let me know ASAP so that I can ship it today.


I wasn't holding by breath, but the tracking number came a few hours later. We'll see what I get on Monday, but I do hope I'll be able to salvage this project now even if it's more painful than I expected.


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## BehemothTheCat (Feb 14, 2022)

The kit arrived this morning. I did a quick inventory and it looks complete. The ballnut on Z-axis came with the mounting plate facing down, so there is no need to flip it on newer mills. I got lucky, but I'm sure there must be others out there in a similar situation who have missed the boat...


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## Christianstark (Feb 14, 2022)

Great news! Maybe they have demystified what may have been some tribal knowledge on running the business, and will be able to move forward with business.


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## kirkrockwell (Feb 23, 2022)

Hi Matt,
I am in that situation, purchased the PM-833TV with intentions to convert for CNC use.  I ordered it in early January, and it is supposed to be delivered this Friday.  I had several calls into Bruce's phone number, and didn't understand why I couldn't get a call back.  I found out here about the bad news.  I suppose they still have the kits in stock, and are hopefully re-grouping to keep going.  But I also imagine the recovery will take time, nothing generates more grief and paperwork than an unexpected death...  

I'm really hoping to salvage this project, do you have contact info for Jose, if it's ok to ask?

I have also contacted David at Arizona CNC Kits, asking if maybe one of his kits would crossover.  He seems willing to work with me if I can get measurements to him for comparison.   When it gets to my shop I'll see what I can find out.  I don't have any experience with the other benchtop models so I don't have any clue what is the same or different between them.  If anyone has the experience I'd welcome the help.

I got hooked on CNC when I worked for a shop that had a Tormach 1100  for production use.  To train myself,  I bought and converted one of the Sherline 5800 desktop units for CNC, using steppers, Gecko drivers, and Centroid Acorn.  I learned Fusion 360  Design and Manufacturing modules and sucessfully made a lot of small parts.  The PM-833TV really looked like a nice step-up option so I worked up a list of stuff to buy following the online example by Dr. D-Flo.


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## chafey37 (Feb 23, 2022)

The heavy metal cnc website is back online!


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## kirkrockwell (Feb 23, 2022)

Great, I see it now.  I knew all I had to do is ask, CNC is so simple  thanks!

I just went there and ordered the PM-833TV kit.


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## BehemothTheCat (Feb 23, 2022)

Glad to hear their website is up again. Jose uses Bruce's old e-mail address <bruce@heavymetalcnc.com>, but as far as I can tell he still doesn't reply to e-mails. I e-mailed him to ask for the installation instructions when I got the package, but he had not responded yet. I hope you do receive your kit, but you should be ready for an uphill battle.

I was able to find another vendor that advertises a PM-833T CNC kit when I was searching for the instructions:






						PRECISION MATTHEWS PM833T Mounting Kit |
					

High-Torque Stepper Motor, Stepper Motor, Driver, Stepper Motor kit, DC Servo Motor, DC Servo Motor kit, Stepper Motor Power Supply, CNC Router, Spindle, and other Components.




					www.automationtechnologiesinc.com
				




https://www.facebook.com/AutomationTechnologiesInc

Out of sheer curiosity, I e-mailed them (and asked my wife to message them on FB) about the availability, but heard crickets. Their instruction manual has been clearly borrowed from Heavy Metal and, judging by the picture, their kit looks almost identical (mine has double ball nuts and comes with ground ball screws). I don't know if they are a reseller of if they make their own clones. 

I suspect my kit came from Bruce's existing inventory and must have been sitting in storage for a while. Here is why:

1. It was exceedingly well packaged yet Jose was able to get it shipped almost immediately
2. There was moderate surface corrosion on the ball screws
3. The mounts have been machined incorrectly - the bearing "spacers" interfere with the inner race of the bearings since the diameter of the opening is too small. This is a well documented problem that was supposedly fixed many months ago.

If my guess is correct, there is no way to tell if they are really back in business or merely trying to get rid of their existing stock. 

Let's hope everything works out. If it does not, I'll be happy to take close up photos and measurements for you.


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## kirkrockwell (Feb 23, 2022)

When I was on the site I made sure to download the PM-833TV installation instructions.  After my order went through, and my credit card was charged, I went outside to move a bunch of snow.

I just came back in and saw 2 emails from HMCNC.  First one was an (I assume automated) confirmation of my order stating that it was being processed.  The second one was from Bruces email address stating "WE ARE CLOSED . NOT DOING BUSINESS" 

The link you showed me to Automated Technologies Inc. has what looks like the base model (non-premium ballscrews) kit.  It allows me to put the kit in the cart, but I didn't go any further. My impression is that they are reps for HMCNC, not making their own kits. 

Thanks for the offer, how close are you to installing your parts?  Close-up pics combined with some measurements I could take might be helpful. Any mounts I could improvise would be pretty crude, I have no way to mill circular pockets or holes for bearings.


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## 7milesup (Feb 23, 2022)

kirkrockwell said:


> Hi Matt,
> I am in that situation, purchased the PM-833TV with intentions to convert for CNC use.  I ordered it in early January, and it is supposed to be delivered this Friday.  I had several calls into Bruce's phone number, and didn't understand why I couldn't get a call back.  I found out here about the bad news.  I suppose they still have the kits in stock, and are hopefully re-grouping to keep going.  But I also imagine the recovery will take time, nothing generates more grief and paperwork than an unexpected death...
> 
> I'm really hoping to salvage this project, do you have contact info for Jose, if it's ok to ask?
> ...


Are you going the Linux route?


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## kirkrockwell (Feb 23, 2022)

I have experience with Centroid Acorn, and want to go with that to reduce the learning curve for this build.  I have never setup Linux before and already have a windows laptop with Acorn that was dedicated to my old Sherline setup.


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## 7milesup (Feb 23, 2022)

kirkrockwell said:


> I have experience with Centroid Acorn, and want to go with that to reduce the learning curve for this build.  I have never setup Linux before and already have a windows laptop with Acorn that was dedicated to my old Sherline setup.


Sounds like a good plan.  I need to move forward on this project but work keeps getting in the way of stuff I really want to do!


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## kirkrockwell (Feb 24, 2022)

Do you already have a CNC conversion kit?  That may be the limiting factor for a while.  I'll post here if the one I ordered today for the 833TV gets shipped to me.  If not it's going to be a slower process, I'll still have a nice manual mill to work on though.  David at Arizona CNC Kits said they are working on a kit for the PM 932V which is a RF45 clone.  Is my PM-833TV an RF45 clone also?


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## ptrotter (Feb 24, 2022)

I have the Arizona CNC kit on my PM-940.  Dave does nice work and is great to deal with.  If he will make a kit for the PM-833, I am sure you will be happy with it.


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## BehemothTheCat (Feb 24, 2022)

It's pretty puzzling that they would resurrect the website and then claim they are "not doing business" the instant an order has been placed. Their advertised shipping time was 3 business days if I remember correctly. I would give them a few days and contact my CC. It did the trick for me (I used PP though) - if they still have inventory, it might work for you too. 

I looked at the kit and can't see why one wouldn't be able to make its functional equivalent on a manual mill. The bearing pockets could be machined on a rotary table. The Z-axis attachment is probably the trickiest part, but should still be doable. The big problem is sourcing the ball screws at a reasonable price. Then, one needs access to a lathe to turn the screws to accept the couplers/pulley.

The rest of the kit is not particularly impressive, which is hardly surprising at that price. The bearings are of rollerblade quality - I know it is a contentious topic, but I'm replacing mine, which will cost me another ~$300 for 3 pairs of midrange 7002 angular contact bearings. Same story with the couplers - they have to go. What worries me is the condition of the ball screws - in addition to corrosion, they are marred all over the place. Nothing major, but it may affect the durability of the ball nuts. Since it is definitely not shipping damage, they were either mishandled or Heavy Metal had bought somebody's surplus/NOS.

I can't be sure, but just looking at the pictures of the PM-932V it seems sufficiently different from my 833, I doubt the kit is going to work.

I may end up going with LinuxCNC, but I will first try grblHAL:






						Grbl
					






					www.grbl.org
				











						grblHAL
					

grblHAL has 39 repositories available. Follow their code on GitHub.




					github.com
				




I bought a breakout board from:









						grblHAL BoB Unkit for Teensy 4.1. - T41U5XBB by Brookwood Design on Tindie
					

Breakout Board for a Teensy 4.1 to run grblHAL for controlling CNC routers, etc.




					www.tindie.com
				




put it together, compiled grblHAL for it, hooked up some old steppers, and it seems to work very well. I still haven't figured out how to handle the MPG part of it, which may turn out to be a deal breaker for me. I'll decide when I get there - for now, I have to install the kit and buy servos etc.




​


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## 7milesup (Feb 24, 2022)

kirkrockwell said:


> Do you already have a CNC conversion kit?  That may be the limiting factor for a while.  I'll post here if the one I ordered today for the 833TV gets shipped to me.  If not it's going to be a slower process, I'll still have a nice manual mill to work on though.  David at Arizona CNC Kits said they are working on a kit for the PM 932V which is a RF45 clone.  Is my PM-833TV an RF45 clone also?


The 833 may very well be an RF45 clone also.  I just looked at the PM website and the 932 looks to be made in China vs the 833 that comes out of Taiwan.  
I do not have a conversion kit.  Converting my 833T to CNC has been on my to-do list for quite some time, I just don't seem to ever have the time.  The mounting blocks and other parts of it can be made in your shop on the 833.  It may be somewhat of a slow process because of the need to disassemble the mill to take measurements and then reassemble it to make parts.  I have a 1440 lathe, so re-working the ends of a ball screw would not be a problem.
Speaking of ball screws, there are many suppliers of ball screws.  I have heard of decent ball screws coming out of China (AliExpress) and other discount areas.  
https://www.roton.com/ is a source I have considered.  
https://www.vxb.com/Ballscrews-s/369.htm
https://www.automation4less.com/ballscrews.htm
https://www.cnczone.com/forums/benc...ball-screws-quality-choice-mapping-buy-7.html (not sure if I can link to an outside forum).
Ball screws come in two flavors, ground and rolled.  For most of us, rolled ball screws are most likely adequate.  Ground ball screws are exceedingly cost prohibitive.


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## BehemothTheCat (Feb 24, 2022)

The premium Heavy Metal kit comes with ground ball screws and it's only $200 more than the standard one with rolled screws.


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## kirkrockwell (Feb 24, 2022)

BehemothTheCat said:


> It's pretty puzzling that they would resurrect the website and then claim they are "not doing business" the instant an order has been placed. Their advertised shipping time was 3 business days if I remember correctly. I would give them a few days and contact my CC. It did the trick for me (I used PP though) - if they still have inventory, it might work for you too.
> 
> I looked at the kit and can't see why one wouldn't be able to make its functional equivalent on a manual mill. The bearing pockets could be machined on a rotary table. The Z-axis attachment is probably the trickiest part, but should still be doable. The big problem is sourcing the ball screws at a reasonable price. Then, one needs access to a lathe to turn the screws to accept the couplers/pulley.
> 
> ...


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## 7milesup (Feb 24, 2022)

BehemothTheCat said:


> The premium Heavy Metal kit comes with ground ball screws and it's only $200 more than the standard one with rolled screws.


That is really interesting.  They have to be sourcing the ground ball screws from China.  I have priced out ground ball screws from here in the US and I thought they were around $1k each.

EDIT:  I just looked at ground NSK from Automation Direct and they are about $1200 for just the X-axis.


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## kirkrockwell (Feb 24, 2022)

Matt, that was my thought to. The 'not doing business' reply came in fast and might have been a leftover autoreply.  I can wait until this time next week to see if they refund the amount, or if they hold onto it I'll expect some shipment info.

I see your point about making the mounts, pockets and bearing holes can be made manually. If the order falls through that can be my backup plan. At that time I might ask you for dimensions/pictures of the mounts, and ballscrew features, for whoever I get to turn them down and add threads. 

I did request the premium ballscrews option for $200 more and have set modest expectations.  Until I get the mechanical parts sorted out I'm holding off on buying servos or drivers etc...


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## BehemothTheCat (Feb 24, 2022)

Kirk, in my case, nothing was being done to get this order taken care of until I filed a claim with PP. Jose got in touch with me literally 10 minutes later. This might have been a coincidence, but I find it unlikely. I don't get why he continues to ignore e-mails now that they brought the website back on. I'd understand if he were slow to reply given the circumstances, but this whole thing is just bizarre. Even if he doesn't want to deal with this again, it makes sense to move their existing inventory rather than let it become scrap. 

My take on it was similar to yours. I didn't want to order the conversion kit until I had the mill and made sure it was in good order. Life and work keep interfering, so it will be a while before I put it together, but that's ok. I enjoy the process more than the outcome. I have a lathe (PM1340GT) on order with PM (paid in full), but have already accepted the possibility I may never receive it. After all, it's a Taiwanese lathe and by the time it's ready to ship, Taiwan may share the fate Heavy Metal CNC. Strange times we live in.

I will take pictures and measure the critical dimensions as I install parts. Don't expect Fusion360 models, but it should be enough to fabricate a replacement.


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## kirkrockwell (Feb 25, 2022)

BehemothTheCat said:


> Kirk, in my case, nothing was being done to get this order taken care of until I filed a claim with PP. Jose got in touch with me literally 10 minutes later. This might have been a coincidence, but I find it unlikely. I don't get why he continues to ignore e-mails now that they brought the website back on. I'd understand if he were slow to reply given the circumstances, but this whole thing is just bizarre. Even if he doesn't want to deal with this again, it makes sense to move their existing inventory rather than let it become scrap.
> 
> My take on it was similar to yours. I didn't want to order the conversion kit until I had the mill and made sure it was in good order. Life and work keep interfering, so it will be a while before I put it together, but that's ok. I enjoy the process more than the outcome. I have a lathe (PM1340GT) on order with PM (paid in full), but have already accepted the possibility I may never receive it. After all, it's a Taiwanese lathe and by the time it's ready to ship, Taiwan may share the fate Heavy Metal CNC. Strange times we live in.
> 
> I will take pictures and measure the critical dimensions as I install parts. Don't expect Fusion360 models, but it should be enough to fabricate a replacement.



Gotcha, I'm thinking a week is long enough to see what kind of response HMCNC will give. I have a note on my calendar to start the refund process after that.  Given that it's been a couple months since Bruce's passing, it may be that his estate and business are already tied up in probate court.  Some states allow for the uninterrupted continuation of a small business after the owner passes, depends on the custom in Texas I suppose.  Would like to think theres a kit sitting there on a shelf waiting for me though.

I bought a new house this month, still don't even have my trailer unpacked.  And for some reason I'm worried about a mill that is going into a shop space that is third on the list to get built out, after my basement shop and my leather studio.  I mean, the mill is supposed to show up on a truck tomorrow, that's the only reason it's in front of me to move on the CNC process.  If I had a kit it would still be summer before it gets much attention...

No kidding!  The first call I'm making after my phone line gets installed tommorrow is to PM to get a 1340GT on backorder .  I guess the PM-833TV and 1340GT hits a sweet spot for a lot of us...  

Thanks, pictures and dimensions would be a great assistance!


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## chafey37 (Feb 26, 2022)

And the hmcnc site is down again


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## INTJ (Feb 26, 2022)

Any of you guys that have converted want to sell me your old X-Axis screw?  Last Jan the movers tipped over my 833T and it hit on the X-Axis screw.  Just got moved into my new house and am setting everything up, and finally have time to get to my Mill. 

I need to X-Axis screw, a bearing, and some other misc parts. Probably the X-Axis nut as well.


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## arizonavideo (Feb 27, 2022)

kirkrockwell said:


> Hi Matt,
> I am in that situation, purchased the PM-833TV with intentions to convert for CNC use.  I ordered it in early January, and it is supposed to be delivered this Friday.  I had several calls into Bruce's phone number, and didn't understand why I couldn't get a call back.  I found out here about the bad news.  I suppose they still have the kits in stock, and are hopefully re-grouping to keep going.  But I also imagine the recovery will take time, nothing generates more grief and paperwork than an unexpected death...
> 
> I'm really hoping to salvage this project, do you have contact info for Jose, if it's ok to ask?
> ...


I'm sad to see Bruce pass and not be able to keep going in the kit businesses. I'm going to start next week on a new CNC kit for the PM-932 and the PM-833.  The big question I have with the 833 is it's a more expensive mill and buyers expect more from it.

 On the ball screws I have been using C7 grade rolled screws with double nuts that I re work to be nice and tight with positive preload. This give really good backlash but they are still a rolled screw so accuracy over distance will only be so good. 
Going to a ground screw will yield  better accuracy over distance but if you run single nuts without hi preload you will still have some backlash. 
Getting the ball nuts pre loaded with hi preload cost even more. Going to double nuts is even more so you soon have screws that cost $500 each. 

If you guys had a choice to make of price performance what might that be? You do have to keep in mind that all these mills are still hobby level and not 4000 pound VMC's. 
Thanks 
Dave Clements-  arizonacnckits.com


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## Crazy Cat (Feb 27, 2022)

Wow! I didn't know about any of this drama. I ordered a kit with the standard screws a couple of months ago anyway, maybe before he had died, and it showed up in less than a week. It definitely isn't a quick bolt on though, and I havent dug into the Z axis yet, but the X and Y are on and work well. There was some modification required, thats for sure. I had to modify quite a bit, but I thought that was just expected with these kits. I still have to do the control cabinet, but I got the servos set up on the bench running and calibrated and it seems to work nicely.  I'm using an ESS, a C82 BOB, and Allen Bradley 3000i servo's (2090-dsd-020 drives and 850 watt servos). It has been a boucou crapload of work for me, with arthritis and the cold, and I haven't even touched the Z axis yet, but man it is fun watching that table fly around!

I would give you (INTJ) my old X axis, but it is bent too! I got the mill for 850 bucks, but the X axis screw was bent.


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## BehemothTheCat (Feb 28, 2022)

Dave,

As of late Bruce was selling the standard kit with C7 rolled screws for ~$1,000 and the premium one with C5 ground screws for ~$1,200. According to their website, both kits use double ball nuts. The premium kit, which I ordered, definitely comes with double ball nuts. I haven't measured anything, but backlash is imperceptible.

The mill itself is not super cheap and neither are the servos etc., so it was a no-brainer for me considering the price difference of $200. Would I have paid a $2,000 premium for better screws? I don't know, but would've definitely paid extra $400-$500 for half-decent angular contact bearings and couplings.


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## kirkrockwell (Feb 28, 2022)

Hi Dave, 
I bet you'll catch a bunch of us guys trying to do the PM-833T/V models!  I am self taught / novice level at CNC. I started by building out a Sherline 5800 CNC ready desktop mill.  Now that it's gone, I intend to use the PM-833TV build as both a continuation of the learning, and in support of my other hobbies and interests.  

My build is going to be $10-$11k in parts and the CNC conversion kit from Bruce would be $1200 of that amount.  My expectations are in-line with "hobby level" accuracy.  My preference would be what looks like your standard 940 kit, that has the C7 ballscrews with double nuts set up to avoid backlash, and including the angular contact bearings.  I intend to follow David Florians example, including the DMM servo upgrades.  I think the X and Y were nema 34 with 1/2 inch shafts and a Z-axis nema 42 with 5/8 inch shaft.  A couple hundred bucks either way isn't going to stop me from doing this.


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## 7milesup (Feb 28, 2022)

kirkrockwell said:


> My build is going to be $10-$11k in parts


Wow. That is 3x to 4x the amount Dave Florian has in his. I would be interested in hearing about the parts you plan on using.


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## kirkrockwell (Feb 28, 2022)

7milesup said:


> Wow. That is 3x to 4x the amount Dave Florian has in his. I would be interested in hearing about the parts you plan on using.



It is about that much, I almost pooped when I tallied up the spreadsheet for my build.  David's website has a bill of materials with links to parts.  








						Benchtop Mill CNC Conversion
					

Dr. D-Flo converts a manual benchtop mill, the PM-833TV, for automated machining in his garage. Learn about the mechanical and electrical systems required for this conversion.




					www.drdflo.com
				




I followed along, adding what I absolutely needed, and discounting parts/pieces I already have.  And skipped the stepper electrical parts, adding instead the AC servo electrical parts.  

Starting from scratch my Precision Matthews order was $6k already for the 833TV, its stand, a 4 inch milling vise, R8 collet set, and clamp down set. That includes shipping/tax with liftgate and into shop delivery.  After that I needed a $1199 conversion kit.  DMM servos (z-axis with brake) total around $1100, and their drivers around $750.  Power supplies and cabinet and all the small parts brought it right up there.

He makes sure to state that for this amount you could get a bare-bones Tormach.  And recommends paying for a turn-key system, if you want to miss all the fun of what looks to be a 2 or 3 month build.   I can only complete this type of project if I follow along with someone who has already done the legwork finding and matching parts, writing it up, and producing videos showing what it's supposed to look like when its finished.  Going the DIY route lets me justify some of that dollar amount as "tuition" and "entertainment" expenses.


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## 7milesup (Feb 28, 2022)

kirkrockwell said:


> It is about that much, I almost pooped when I tallied up the spreadsheet for my build.  David's website has a bill of materials with links to parts.
> 
> 
> 
> ...


Ahhhh.  That makes more sense now that you are including the mill and all of its accouterments.   I already have the mill, which I have been using for a few years now.  
I did consider going the Tormach route but my understanding is that there is no manual mode.  I would like the option of turning a handwheel should I have the need.


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## kirkrockwell (Feb 28, 2022)

7milesup said:


> Ahhhh.  That makes more sense now that you are including the mill and all of its accouterments.   I already have the mill, which I have been using for a few years now.
> I did consider going the Tormach route but my understanding is that there is no manual mode.  I would like the option of turning a handwheel should I have the need.


When I built my Sherline I sourced steppers with dual shaft to continue using the handwheels.  I rarely did, but instead used my MPG to work manually.


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## Crazy Cat (Feb 28, 2022)

A lot of the work involves machining the mounts to fit your motors, and opening up the base and table to accommodate the ballnuts and couplings, machining the oil grooves and tapping out the fitting holes. I needed a lathe for the ball screw ends because my motors have 16mm shafts, and one of the screws was an inch short.  If you just bolt everything up, you just run into problems with the existing holes being slightly off and miss-alignment problems. The base required quite a bit of grinding and sawzall work to accommodate the y axis screw and nut.

I bought my servos and drives off of ebay for a fraction of what they would cost new, but then there is a lot of messing with them to get them configured correctly, and the cost of cables and connectors. Right now I'm putting the control cabinet together, and there is the cost of the power supplies, contactors, breakers, din rails, filters, switches, limit switches, wiring, the cabinet, oil lines, pump, relays, etc....

To do it correctly it is quite a bit of work, and money, and its rewarding and fun as well. Just be prepared for all of the incidental work and costs.


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## 7milesup (Feb 28, 2022)

kirkrockwell said:


> When I built my Sherline I sourced steppers with dual shaft to continue using the handwheels.  I rarely did, but instead used my MPG to work manually.


I am assuming that the handwheels felt "coggy?"  From my understanding the larger the stepper motor the more pronounced the cogging effect.  I wonder how that would play out on this mill because the steppers will be considerably larger than on the Sherline.  Servos would not have that effect when powered off, is that correct?


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## kirkrockwell (Feb 28, 2022)

7milesup said:


> I am assuming that the handwheels felt "coggy?"  From my understanding the larger the stepper motor the more pronounced the cogging effect.  I wonder how that would play out on this mill because the steppers will be considerably larger than on the Sherline.  Servos would not have that effect when powered off, is that correct?


Yes, the cogging was noticable even on the nema 24 steppers.  Also when spinning the handwheel faster, the stepper would generate power and illuminate the lights on the driver even with everything turned off.  That could be stopped by disconnecting the stepper leads.  

As I understand the AC servos are free to spin when unpowered.  That's why the z-axis servo needs to have a brake that applies when power is off,  or the weight of the whole axis can cause the head to ride down the ball screw and impact the table/vise.


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## arizonavideo (Mar 4, 2022)

kirkrockwell said:


> Hi Dave,
> I bet you'll catch a bunch of us guys trying to do the PM-833T/V models!  I am self taught / novice level at CNC. I started by building out a Sherline 5800 CNC ready desktop mill.  Now that it's gone, I intend to use the PM-833TV build as both a continuation of the learning, and in support of my other hobbies and interests.
> 
> My build is going to be $10-$11k in parts and the CNC conversion kit from Bruce would be $1200 of that amount.  My expectations are in-line with "hobby level" accuracy.  My preference would be what looks like your standard 940 kit, that has the C7 ballscrews with double nuts set up to avoid backlash, and including the angular contact bearings.  I intend to follow David Florians example, including the DMM servo upgrades.  I think the X and Y were nema 34 with 1/2 inch shafts and a Z-axis nema 42 with 5/8 inch shaft.  A couple hundred bucks either way isn't going to stop me from doing this.



I read Davids build list and its fine but you can make changes. 

The DMM 86N is just fine for all axes. It is a 750 watt servo and most the time you will be milling with 60 watts of power on the X and Y. The only question is the Z and a break. The 86N has been used lots for the PM-940 with no break.  If you have medium preload on the AC bearing and snug gibs the head wont drop. The larger 32mm Z screw also has a bit more friction. On my 940 the head does not drop but with the power off and if I hammer on the vise and vibrate the mill it will go down some. I still have a 25mm screw.

I still like some of the closed loop steppers, mostly the Stepper Online drivers are good.  1200 oz for the X and Y and 1600 for the Z. 

If you guys want to measure up the  parts for me I can make them.  We can do it here if you want. 

The strange thing here is my best friend from grade school and for many years after was named Bruce Nelson.  He had heart problems and died 4 years ago.  Still miss hims sometimes....
Thanks
Dave


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## kirkrockwell (Mar 4, 2022)

arizonavideo said:


> I read Davids build list and its fine but you can make changes.
> 
> The DMM 86N is just fine for all axes. It is a 750 watt servo and most the time you will be milling with 60 watts of power on the X and Y. The only question is the Z and a break. The 86N has been used lots for the PM-940 with no break.  If you have medium preload on the AC bearing and snug gibs the head wont drop. The larger 32mm Z screw also has a bit more friction. On my 940 the head does not drop but with the power off and if I hammer on the vise and vibrate the mill it will go down some. I still have a 25mm screw.
> 
> ...


Good to know about the z-axis, that 940 is a heavier machine.  I used Stepper Online before, and on this build I want to use the upgrades, keeping in line with the 'more premium' nature of the PM-833VT.  But if I don't need that 1300 watt braked motor it would save a chunk, thanks for the practical advise.  

I emailed you about my situation.  The mill is in my shop waiting to be torn into.


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## BrokenSpoke (Aug 12, 2022)

Is there a final verdict on this? I was literally ready to buy the conversion kit based on the DFlo video (bought the mill a year ago - waiting to save up enough spare cash for CNC)... but, apparently the company that made the conversion kit is gone? Any other conversion kits for the 833TV? Or at least some drawings/parts list I can purchase?


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## chafey37 (Aug 12, 2022)

BrokenSpoke said:


> Is there a final verdict on this? I was literally ready to buy the conversion kit based on the DFlo video (bought the mill a year ago - waiting to save up enough spare cash for CNC)... but, apparently the company that made the conversion kit is gone? Any other conversion kits for the 833TV? Or at least some drawings/parts list I can purchase?


Ditto


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## BrokenSpoke (Aug 14, 2022)

chafey37 said:


> Ditto


This just came up in my feed! Looks like there may be a solution in weeks...


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## chafey37 (Aug 14, 2022)

Yaaaaaassssss


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## Gehirnesser (Nov 14, 2022)

Hello, is anyone willing to take measurements of their kits for all of us who were too late to order them? 

Thanks!


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