# New PM-727V arrived today, Happy ??



## GTPI (Jun 26, 2020)

My new machine is DOA!    Did I miss something ? Yes It's got power, spindle just chatters occasionally when the forward or reverse buttons are pushed.

Besides that it's perfect, I gave it a quick clean and now that I won't be making any chips I'll have the whole weekend to deep clean and setup.

The only small item that I found is that the arm that the DRO is mounted on is too small for the column mounted bracket so it flops around when tight, a few nylon 

washers will remedy this.  

   Well regardless, my new mill is really nice! I'm pleased with PM's service so far and I'm certain this will be resolved quickly. I'll be sure to update once my mill is

 fully operational.


----------



## mikey (Jun 26, 2020)

Congrats!! Sorry to hear there is a problem but Matt will make it right.

Now where are the PICS??


----------



## tweinke (Jun 26, 2020)

I would send an email tonight or as soon as practical. If nothing else it will give them a chance to be ready for your call, or you may be surprised by a response over the weekend which is what happened for me when i had an issue. As Mikey said they will make it right.


----------



## GTPI (Jun 26, 2020)

mikey said:


> Congrats!! Sorry to hear there is a problem but Matt will make it right.
> 
> Now where are the PICS??


                       Thanks , I had friends lined up to help me but when the delivery truck arrived they were gone. I spent the next three hours getting the mill in my house by myself.   It's amazing what one can do when necessary .
 So it's hotter than hell in SW Florida but I was determined to get my new mill inside before the rain storm that was coming . My efforts were fueled by the anticipation of my new mills first chip!   It was a bit of a let down to say the least.


----------



## GTPI (Jun 27, 2020)

tweinke said:


> I would send an email tonight or as soon as practical. If nothing else it will give them a chance to be ready for your call, or you may be surprised by a response over the weekend which is what happened for me when i had an issue. As Mikey said they will make it right.


       Thanks, email has been sent to PM. hopefully I'll hear back early in the week.


----------



## Skowinski (Jun 27, 2020)

I'm sure PM will get in touch with you right away and make it right.  I've contacted them about 5 or 6 times via email asking about machines, and got very quick responses every time.

Congrats on the new milling machine!


----------



## markba633csi (Jun 27, 2020)

Unplug the machine and check all the wire terminal connections- something may have come loose during shipping
-Mark


----------



## GTPI (Jun 27, 2020)

markba633csi said:


> Unplug the machine and check all the wire terminal connections- something may have come loose during shipping
> -Mark


           Thanks, I removed the front panel and checked all connections to be sure they are in place but that's as far as I went.  I haven't checked connection at the motor.
     While being very careful if I advance the spindle slightly it will attempt to move then nothing.


----------



## pontiac428 (Jun 27, 2020)

GTPI said:


> Thanks , I had friends lined up to help me but when the delivery truck arrived they were gone. I spent the next three hours getting the mill in my house by myself.   It's amazing what one can do when necessary .



Boy can I ever relate to this.  In the end it's always my stuff, my problem, but it's amazing what can be accomplished with the right kind of pressure and a fistful of ibuprofen.


----------



## rwm (Jun 27, 2020)

pontiac428 said:


> fistful of ibuprofen.



LOL!


----------



## GTPI (Jun 27, 2020)

Just wanted to make it known that someone from PM emailed me today to reassure me that they will look into this further on Monday,  I was asked to try and disconnect the speed sensor and power to it and see if that changes anything.  I'll report back soon!
       UPDATE: No luck, pulled the speed sensor as reccomended,  nothing. Checked all the connections and all pass, it's time to start throwing parts at it!  If it were an AC motor I would say its faulty but seeing that I'm not sure how the board works and I don't have a working DC meter I will wait for Monday.
    The motor will try to run and spins maybe one or two revolutions then locks up yet when I cut power the shaft spins freely.  Acts like a bad motor.


----------



## markba633csi (Jun 27, 2020)

No that sounds like a bad controller- anyhow, Matt will get you going


----------



## markba633csi (Jun 27, 2020)

typo


----------



## GTPI (Jun 27, 2020)

markba633csi said:


> No that sounds like a bad controller- anyhow, Matt will get you going


     Thanks, There's nothing on this mill that looks like shipping could hurt it unless it was a really rough ride, the crate was perfect but it had been opened and sealed prior to delivery . 
  PM told me that they do run them before before they ship. 
     So at the end of the day I'm confident it will be taken care of, I will just have to delay my happy dance for a few days. 
   Tomorrow I will locate a engine crane and get my mill lifted onto the base, I can't just keep cleaning it


----------



## tweinke (Jun 27, 2020)

I understand the feeling of a new machine that wont run, frustrating is the least of it. Matt and the gang at QMT will get you going soon so the happy dance can go on!


----------



## GTPI (Jun 29, 2020)

markba633csi said:


> No that sounds like a bad controller- anyhow, Matt will get you going


       After a short diagnostic over the phone they will be sending me a replacement motor controller and a replacement speed control.   They may have been able to check further but I don't have a DCV meter.
      Hopefully we get it the first time, I was told DC motors rarely go bad!
    I have had plenty of time,  don't think this mill will ever be Q-tip clean again.  LOL


----------



## GTPI (Jul 10, 2020)

GTPI said:


> After a short diagnostic over the phone they will be sending me a replacement motor controller and a replacement speed control.   They may have been able to check further but I don't have a DCV meter.
> Hopefully we get it the first time, I was told DC motors rarely go bad!
> I have had plenty of time,  don't think this mill will ever be Q-tip clean again.  LOL


                  Still waiting!


----------



## wrmiller (Jul 10, 2020)

Did you call PM and ask them the status?


----------



## GTPI (Jul 11, 2020)

wrmiller said:


> Did you call PM and ask them the status?
> [/QUOTE                Well its been dead since new, PM got me a controller and speed dial today, nothing is any different so another attempt .  Yup  Im a bit disapointed.


----------



## tweinke (Jul 11, 2020)

Dang it. Stick with it, I'm sure they will resolve the issue.


----------



## GTPI (Jul 11, 2020)

tweinke said:


> Dang it. Stick with it, I'm sure they will resolve the issue.


          So far I have had to make all the calls, a little follow up customer service would go a long way


----------



## tweinke (Jul 11, 2020)

I wonder how the whole virus thing figures into this, might be from limited staff. I sure hope so at least. I had excellent service when i needed help with my PM-727M


----------



## GTPI (Jul 12, 2020)

Well I felt it was a bad motor, even so I was sent a controller and a speed controller which required soldering to the harness , I'm shocked it was less the 1'leads and connector to make it plug&play.  This mill takes an odd  motor (1.5hp dc)   .
   They didn't have the parts I received in stock so I guess a motor could be a problem too.       I waited so long for something so disappointing.


----------



## GTPI (Jul 14, 2020)

Well I  spoke to Mike, my only contact. The parts that were sent didn't work so he will be sending me a new motor. I'm still looking forward to my new mill,  just wish it had gone better.


----------



## jwmelvin (Jul 14, 2020)

Frustrating process you are going through. I really hope the new motor finally gets it squared away.


----------



## GunsOfNavarone (Jul 17, 2020)

Wow...yeah, that stings a bit.


----------



## Splat (Jul 22, 2020)

Any update?


----------



## GTPI (Jul 22, 2020)

Splat said:


> Any update?


                   I  am still waiting, I was told a new motor needs to come from China. I was also contacted for my mills serial number, not sure why they don't have it on file!   Tech support claims to be working hard on it.   I did tell them that they should send a truck to pick it up.    Funny, but I would gladly let it go.


----------



## DaveV (Jul 23, 2020)

GTPI said:


> Well I felt it was a bad motor, even so I was sent a controller and a speed controller which required soldering to the harness , I'm shocked it was less the 1'leads and connector to make it plug&play.  This mill takes an odd  motor (1.5hp dc)   .
> They didn't have the parts I received in stock so I guess a motor could be a problem too.       I waited so long for something so disappointing.


Just wondering about the bldc motors that seem to be commonly used in many small mills.  Does anyone know how reliable they are in general, or in comparison to induction motors.  Asking because I have no experience with these motors and have considered a smaller mill, but given your experience I'm starting to wonder if I should avoid machines with bldc motors.  I know a sample of one is not indicative of peoples general experienc, but I still have to wonder.  

So how long should a bldc motor and controller be expected to last?  I have induction motors that are decades old.  Should I reasonably expect a bldc motor to last as long?  Also how universal are these motors?  If PM is no longer in business down the road how difficult would it be to source a replacement motor.

I know adding this question to this thread may not be the best place for it, but it was GTPI's experience that really got me thinking about this.


----------



## macardoso (Jul 23, 2020)

DaveV said:


> Just wondering about the bldc motors that seem to be commonly used in many small mills.  Does anyone know how reliable they are in general, or in comparison to induction motors.  Asking because I have no experience with these motors and have considered a smaller mill, but given your experience I'm starting to wonder if I should avoid machines with bldc motors.  I know a sample of one is not indicative of peoples general experienc, but I still have to wonder.
> 
> So how long should a bldc motor and controller be expected to last?  I have induction motors that are decades old.  Should I reasonably expect a bldc motor to last as long?  Also how universal are these motors?  If PM is no longer in business down the road how difficult would it be to source a replacement motor.
> 
> I know adding this question to this thread may not be the best place for it, but it was GTPI's experience that really got me thinking about this.



I work in the automation industry and while I cannot comment on BLDC motors, I can on AC servo motors. They are surprisingly the same motor hardware more or less, except the AC motor is controlled a bit more intelligently. Since there are no brushes, they can last a very long time (decades) under constant use. That assumes the customer installs them within the design limits and in a clean environment. It is much more common for the control electronics to die.

That being said, induction motors are the simplest device out there and can last indefinitely with bearing maintenance.


----------



## DaveV (Jul 23, 2020)

macardoso said:


> I work in the automation industry and while I cannot comment on BLDC motors, I can on AC servo motors. They are surprisingly the same motor hardware more or less, except the AC motor is controlled a bit more intelligently. Since there are no brushes, they can last a very long time (decades) under constant use. That assumes the customer installs them within the design limits and in a clean environment. It is much more common for the control electronics to die.
> 
> That being said, induction motors are the simplest device out there and can last indefinitely with bearing maintenance.


Thank you, that helps.   As I said before, I have no experience with these motors and do not know what to expect ... good or bad, so any real world feedback is most welcome.


----------



## GTPI (Jul 27, 2020)

31 Days have passed.  I have been nothing but patient . Thoughts?


----------



## Splat (Jul 27, 2020)

They might be waiting for a big(ger) order from China to be shipped with which they'll include your motor. Otherwise, it would be $$ to just ship a motor from China but I could be wrong. Did they give you any estimated date?


----------



## Dhal22 (Jul 27, 2020)

GTPI said:


> 31 Days have passed.  I have been nothing but patient . Thoughts?




That is a statement and question for Matt/PM.


----------



## Janderso (Jul 27, 2020)

Shipping is a real big problem right now.
I don’t know if it applies but it took UPS a
over a month to ship a package 142 miles in Northern Ca.
The package arrived damaged but the item was OK.
I understand Fed Ex is experiencing a similar overload problem.


----------



## erikmannie (Jul 28, 2020)

GTPI said:


> 31 Days have passed.  I have been nothing but patient . Thoughts?


You are clearly going through a frustrating start with your new machine. I am confident that your patience will have you making chips at some point. I would bet everything I own that PM is doing everything humanly possible to rectify your issue.

With all of this removing and replacing, you are probably going to end up with an enviable stock of replacement parts for your machine. Those spare parts may turn out to be gold years down the road.

Hopefully you have other machines to spend time with while you endure this excruciating trial of your patience.

I also wonder how much time COVID-19 is contributing to these delays. COVID-19 has cancelled or delayed almost every single thing that I have planned in 2020.


----------



## GTPI (Jul 28, 2020)

erikmannie said:


> You are clearly going through a frustrating start with your new machine. I am confident that your patience will have you making chips at some point. I would bet everything I own that PM is doing everything humanly possible to rectify your issue.
> 
> With all of this removing and replacing, you are probably going to end up with an enviable stock of replacement parts for your machine. Those spare parts may turn out to be gold years down the road.
> 
> ...



            Thanks, I appreciate the fact that members here try to help me retain my sanity during this waiting game.

I do realize the issues that COVID-19 has caused, I tested positive and the first symptoms showed mid June.

I have been through hell but seem to be making a speedy recovery and hope to get negative test results soon.

   As far as the mill goes, Mike from tech support has been working on getting my replacement motor.

I guess i'm just not aware of the added difficulties when having to deal with part coming from China.

          Thank you and to everyone that took time to help.


----------



## ericc (Jul 28, 2020)

Brushless DC motors can be fiddly.  They are bundled with their controllers, and they either work or they don't.  Can PM provide you with a temporary AC induction motor that fits until they are able to source a BLDC motor with the correct mounting pattern?  It might be awhile.  I'd be going nuts, but in the grand scheme of things, a few months is not all that long.  I have been rebuilding my sad old basket case South Bend lathe for years now.  But at least it's making chips.  Boy does it ever make a lot of chips.


----------



## higgite (Jul 28, 2020)

ericc said:


> .... but in the grand scheme of things, a few months is not all that long.


A matter of perspective. Using myself as an example, I would agree that a few months out of my first 75 years is not all that long. I dare say a few months out of my hopefully remaining years would be much more significant with proportionate frustration. Just saying.  

Tom


----------



## ericc (Jul 28, 2020)

Hmmm.  Tom, you have a good point.  I would be asking PM about that induction motor to at least lend you for a few months.


----------



## erikmannie (Jul 28, 2020)

I know that there is a PM shipment from Taiwan on its way here & due in early August. Maybe your replacement motor is on that ship.


----------



## GunsOfNavarone (Jul 29, 2020)

Man, you have been an incredible customer. I bought my PM-727m used and it needed some things. I was happy to pay for them and yet I was sent out to find them on my own...at least 5 times. Weird, they have their reasons...whatever, but if I bought a brand new machine and posted my experience here for others to view, well, this is as good as it gets? A very patient man you are no doubt, but when will that fuse be used up? Hopefully they are lighting fires under peoples feet because as of now, it's been too long. HEAVEN FORBID that's not the problem. I can say mines in great shape now and will probably be for sale soon...just saying.


----------



## GTPI (Jul 30, 2020)

A  new motor arrived yesterday , I went right to work.  The install went well other than one of the factory installed connectors was incorrect and would not plug into the motor controller , it was a simple swap with the original .   As per the manual the first thing I did was to run it through all gear settings which I did in forward and reverse .
   Here are a few things noted
 A.) The forward and reverse buttons are reversed , don't know what caused it, motor or controller. Should be an easy fix.
 B.)  When set at H-3 running at approximately 2500 rpm the speed will fluctuate by a few hundred rpm, sounds like it is straining when the rpm drop.
 C.) The lower spindle bearing gets very hot after just a few minutes of running at higher speeds
   So my mill is running which is a step in the right direction but QC is in need of help!


----------



## jwmelvin (Jul 30, 2020)

A step in the right direction indeed. Hope you sort out the last few issues.


----------



## wrmiller (Jul 30, 2020)

Just my opinion here, but I have owned several Chinese bench mills and I learned to change out the spindle bearings as soon as I could. Head runs cooler, smoother, and the surface finish improves significantly.


----------



## GunsOfNavarone (Jul 30, 2020)

I can't say what my PM was like from new as I bought it used however, when I replaced the spindle bearings, a bit too much grease and the temp rises quickly. Between breaking in the bearings and displacing a bit of grease, I'd be willing to bet that will change over time. Perhaps set it to run 20 mins a day regardless if its cutting anything. Smooth waters from here brother!


----------



## GTPI (Jul 30, 2020)

GunsOfNavarone said:


> I can't say what my PM was like from new as I bought it used however, when I replaced the spindle bearings, a bit too much grease and the temp rises quickly. Between breaking in the bearings and displacing a bit of grease, I'd be willing to bet that will change over time. Perhaps set it to run 20 mins a day regardless if its cutting anything. Smooth waters from here brother!



             I think you nailed it !  I have been running it in all gears both forward and reverse, it has improved.   I noticed the head gets pretty warm also but it's probably normal. I will check the actual temp next time.  I may take wrmiller's advice and look into upgrading spindle bearings.  
Thanks much


----------



## tweinke (Jul 30, 2020)

It is good to hear you have a running machine! The spindle gets warm on my PM-727M also. I have never measured the temp but it certainly isnt too hot to hold on to. my machine got quieter after it got some time on it. I think I will soon be pulling the spindle to re grease the bearings so I will probably replace them with a better quality bearing with good grease.


----------



## wrmiller (Jul 30, 2020)

Warm, even mildly hot is OK guys. But when you can't keep your hand on the head for very long it's TOO hot. 

Even with class 7 bearings things still get warm. Friction creates heat, and with a new machine, things need to wear/break in a bit. But that's just my opinion of course.


----------



## GTPI (Jul 31, 2020)

wrmiller said:


> Warm, even mildly hot is OK guys. But when you can't keep your hand on the head for very long it's TOO hot.
> 
> Even with class 7 bearings things still get warm. Friction creates heat, and with a new machine, things need to wear/break in a bit. But that's just my opinion of course.



            Just thought I'd check temps,  after running in H-3 (gear selection) for 15-20 minutes side of motor was 142, top of head near motor 116, all other parts of head 102-109,  spindle bearings 113. Temp taken with digital laser thermometer, motor speed kept high but not max to provide best fan efficiency.   I think it will only get better with more run time.      
         Anthony


----------



## mikey (Jul 31, 2020)

GTPI said:


> Just thought I'd check temps,  after running in H-3 (gear selection) for 15-20 minutes side of motor was 142, top of head near motor 116, all other parts of head 102-109,  spindle bearings 113. Temp taken with digital laser thermometer, motor speed kept high but not max to provide best fan efficiency.   I think it will only get better with more run time.
> Anthony



Are you able to directly measure temps at the spindle bearings? I mean shoot the laser directly at the upper and lower spindle bearings. If so, most quality bearings should not get above ~100 degree C. You cannot determine if the bearing is running hot by measuring the temp of the housing - too many variables.

For those of you who are thinking about re-packing your spindle bearings (tapered roller bearings), remember that you should clean the bearing thoroughly, then pack only 1/4 to 1/3 of the bearing with a high quality bearing grease. Overpacking the bearing like you do with wheel bearings will result in overheating and may destroy the bearing. You should also slowly run in the bearing after repacking it to allow the grease to warm up and re-distribute.


----------



## GunsOfNavarone (Jul 31, 2020)

I think when I read PM's suggestion, it was really low, like 20-30% coverage...definitely not a "packing" style like wheel bearing. There really isn't much grease needed at all so get that Keblex (sp?) one small tube is plenty and it's pretty light stuff. You don't want wheel bearing grease. My bearings stay right at 70-90* (depending the ambient room temp.) I'm pretty confident you'll be fine...don't sweat it and just plan on changing out to better bearing when the time comes. Hopefully you're up and running after all this time!


----------



## GTPI (Jul 31, 2020)

mikey said:


> Are you able to directly measure temps at the spindle bearings? I mean shoot the laser directly at the upper and lower spindle bearings. If so, most quality bearings should not get above ~100 degree C. You cannot determine if the bearing is running hot by measuring the temp of the housing - too many variables.


           Yes I agree,  in my post I detailed temperatures,  where they were taken and method used. I believe I covered it exactly as you mentioned,  see the full results, the spindle bearings ran at 113
          The machine is new so as far as the quality of the bearings goes they are what PM installed, the amount of grease used is unknown .
       If possible I'd appreciate more info on replacing the spindle bearings and where to source high quality replacements. 
        Thanks
   Anthony


----------



## GunsOfNavarone (Jul 31, 2020)

I can pull the info from Amazon where I got mine, bearing replacement is very easy, though I never replaced the bearings at the top as I was unsure on those even though I have them. (not the top spindle, the ones you see around draw bar) They aren't part of the issue anyway.
30207 Nachi
30205 Nachi


----------



## GTPI (Jul 31, 2020)

GunsOfNavarone said:


> I can pull the info from Amazon where I got mine, bearing replacement is very easy, though I never replaced the bearings at the top as I was unsure on those even though I have them. (not the top spindle, the ones you see around draw bar) They aren't part of the issue anyway.
> 30207 Nachi
> 30205 Nachi



                     So  the bearings that you pointed out are housed in the quill or on the spindle?  Will I need to  press them off & on.   Any details on removal would be helpful, I want to get familiar with servicing them before I have a problem .
        Thanks much


----------



## mikey (Aug 1, 2020)

GTPI said:


> Yes I agree,  in my post I detailed temperatures,  where they were taken and method used. I believe I covered it exactly as you mentioned,  see the full results, the spindle bearings ran at 113
> The machine is new so as far as the quality of the bearings goes they are what PM installed, the amount of grease used is unknown .
> If possible I'd appreciate more info on replacing the spindle bearings and where to source high quality replacements.
> Thanks
> Anthony



Okay, that's about 45 deg. C, which is normal operating temp for a spindle bearing.


----------



## GunsOfNavarone (Aug 1, 2020)

I think you'll be fine for a while, this, like all things will pass....
I'll see if I can put some pictures together, it's probably 8 steps, 2 hidden grub screws, one semi-tricky tension spring. Bearings are a snug fit, never had to pull out a bearing puller/race puller/shop press. I literally could do it in 30 minutes now (had to play with bearing pre-load so I had to do it 3 times in a row. 
You might as well get your money's worth out of those bearings, surprisingly, life didn't really improve with bearing replacement.
Did you get that surging rpm thing figured out?


----------



## GTPI (Aug 1, 2020)

GunsOfNavarone said:


> I think you'll be fine for a while, this, like all things will pass....
> I'll see if I can put some pictures together, it's probably 8 steps, 2 hidden grub screws, one semi-tricky tension spring. Bearings are a snug fit, never had to pull out a bearing puller/race puller/shop press. I literally could do it in 30 minutes now (had to play with bearing pre-load so I had to do it 3 times in a row.
> You might as well get your money's worth out of those bearings, surprisingly, life didn't really improve with bearing replacement.
> Did you get that surging rpm thing figured out?



         Thanks for the info. I never found the cause of the surging , I went over all connection, it only did it the first time it ran and never again. Maybe it was a bat in the bearings, I'll check the oil.
     I did notice that the advertised max rpm is 3000, this machine will run smooth at 3500 rpm. Maybe the motor swap? sure it's OK.
 What I noticed is that it will operate from 0 to the max rpm stated for each gear, the low speed in each range is just recommend startling point correct ? Hope that made sense.  (new guy stuff)
    Thanks
Anthony


----------



## macardoso (Aug 1, 2020)

I have a G0704 - Different machine but hopefully applicable. I've run the factory original spindle bearings as well as 2 replacement sets of angular contact bearings (first set I installed poorly and destroyed). The most recent set was packed with Kluber IsoFlex NBU 35 for a 30% fill.

My spindle will get up to 140*F @ 5000 rpm. I can run it all day long at this temp and I have zero problems. It has been running for years this way. Personally I'd be thrilled with 115*F.

Sounds like you are up and running, time to start making chips. You can always revisit issues down the road.


----------



## GunsOfNavarone (Aug 1, 2020)

@macardoso  holy moly! 5K rpm's? Is this the stock setup? Yes Kluber is the grease I used but couldn't remember the name...it's crazy expensive but for a spindle bearing replacement, you don't need much. I really don't think GTPI needs new bearings at this point, but if he's just gathering info for someday, I get that, this place is invaluable for that.
Your 5k versus (well my PM only gets up to 1750 prm, OP's goes to 3 k?) I'd expect much higher temps. But again, I don't believe he has any issues to worry about. His purchase has had plenty already, I think he's a bit shell shocked, don't blame him.


----------



## Buffalo21 (Aug 1, 2020)

Damn 5000 rpm!!

My Rockwell mill does about 6650 rpm, at max gearing, I ran it there long enough to get a speed reading after the mill transmission build, according to the original speed tag, 6300 rpm was the original max speed. I hopefully never need that speed, the mill did it, but it did not sound happy doing it. About 2 weeks ago, I did a job at roughly 3100-3200 rpm, I had no issues, but the overall mechanism sound was a little too busy for me. I did a job today at roughly 1500 rpm and everything sounded good.


----------



## macardoso (Aug 2, 2020)

GunsOfNavarone said:


> @macardoso  holy moly! 5K rpm's? Is this the stock setup? Yes Kluber is the grease I used but couldn't remember the name...it's crazy expensive but for a spindle bearing replacement, you don't need much. I really don't think GTPI needs new bearings at this point, but if he's just gathering info for someday, I get that, this place is invaluable for that.
> Your 5k versus (well my PM only gets up to 1750 prm, OP's goes to 3 k?) I'd expect much higher temps. But again, I don't believe he has any issues to worry about. His purchase has had plenty already, I think he's a bit shell shocked, don't blame him.



No, not stock at all. I have a 5000 rpm servo belted 1:1 to the spindle. I also have the quill disabled since my CNC used the column for Z axis motion. I started talking about my spindle modifications on posts 4 and 10 here. Perhaps the info might help others. When I ran the spindle stock, the bearings gave me no trouble. I wanted to comment above to just say that if my bearings survive for a long long time at 140*F, I don't think there is any issue with 115*F.

With the design, there isn't any reason I couldn't change the pulleys to get 7.5-10k rpm but I like the low speed torque.









						G0704 CNC AC Servo Rebuild (Picture Heavy)
					

Hi All,  About 5 years ago I completed a CNC conversion of a Grizzly G0704 milling machine. Like everyone at that time I chose to go with the Hoss Machine style conversion as there were not many options on the market. I was not comfortable designing my own system at the time since I was just...




					www.hobby-machinist.com
				




The kluber is expensive, but I found a place selling small $30 tubes which is more than I need. I got some dosing syringes from out cats' vet to measure out the grease, and used free space data from NSK bearing catalog to calculate the grease fill for my bearings.

Feel bad for OP on his luck. I kind of expect that if you are buying a machine under 10-20k, you're going to have something broken or not well made on it. Some are easier to fix than others.


----------



## GunsOfNavarone (Aug 2, 2020)

@macardoso not to lead this too far off topic, but is that the main consideration that is limited on how much speed a spindle can handle? The reason I ask is, I changed my lathe to VFD and I can now get over 4k now, for some reason that doesn't feel safe. If I were able to source very good, angular contact bearings, does this now make this achievable? (in your opinion?)


----------



## macardoso (Aug 2, 2020)

GunsOfNavarone said:


> @macardoso not to lead this too far off topic, but is that the main consideration that is limited on how much speed a spindle can handle? The reason I ask is, I changed my lathe to VFD and I can now get over 4k now, for some reason that doesn't feel safe. If I were able to source very good, angular contact bearings, does this now make this achievable? (in your opinion?)



Bearings have a factor called the DN factor. It is complicated to use, but it determines the maximum application speed, base oil viscosity, and bearing life time at a given load, speed, and temperature.

Good taper roller bearings with appropriately selected oil/grease can give performance into the high 1000s or even 10k+ rpm. You don't need angular contact bearings just because of that. You can probably run your bearings that fast, but you might need to select a different oil, and you will wear them faster. AC bearings will run faster, but also will reduce the spindle rigidity compared to a taper roller unless very carefully designed (additional bearings). I can't say for sure if it is appropriate to run your lathe that fast. * I would be very concerned about the max speed of your chuck!* They can explode if you exceed their rated speed.


----------



## mksj (Aug 2, 2020)

GTPI said:


> Thanks for the info. I never found the cause of the surging , I went over all connection, it only did it the first time it ran and never again. Maybe it was a bat in the bearings, I'll check the oil.
> I did notice that the advertised max rpm is 3000, this machine will run smooth at 3500 rpm. Maybe the motor swap? sure it's OK.
> What I noticed is that it will operate from 0 to the max rpm stated for each gear, the low speed in each range is just recommend startling point correct ?


Surging as well as elevated bearing temperature are not uncommon with a new machine because everything is tight, it is always recommended that you slowly break in the bearings/gears by running the machine for a period of time starting at the lowest gear range and then successively go to the next higher speed. Running each for 20-30 minutes at each range first in forward and then in reverse, and if the bearings get hot allowing them to cool. Wanking a machine out at top speed out of the box is not a good idea. I had a gear head mill in the past, would go to 3000 RPM, the bearings/spindle head would get so hot you didn't want to put you hand on it for more than a few seconds. When I changed the gear head oil to a synthetic, it made a significant difference in head temperature and top speed. In reality, you rarely need more than 2000 RPM, unless you are running a small cutter with coolant and//or CNC. I now have a VFD knee mill with a direct drive, can't recall ever going past 3000 RPM even though it will go to 5K. 

You have a speed pot to adjust the speed but it does not mean the usable speed is from 0-100. A reasonable speed range is 50-100% depending on the design and motor specs, factory VFD mills and lathe are usually 2 or 3 speed with a usable speed range of 20-100% with the 3 phase motors being run at 3X their base speed. So it is a matter of Hp and design, as well as the work load.

Glad you are up and running, DOA machinery does occur or early electronic failure, but once everything is working electronics should go for many years without issues. When I had issues with my gearhead mill, I waited for 6 months for a basic replacement part and had to jump through hoops to prove it was defective. The distributor closed up shop later on, so warranty did ot do me any good, and parts if something else went out I would have been toast. Buying subsequent machinery, service and parts availability played an important part in my choice of machines. It is often a waiting game if a part is not on the shelf, in particular during these times.


----------



## BGHansen (Aug 2, 2020)

Curious what PM has to say about your experiences with this new mill. Replacing spindle bearings on a brand new machine? Reading posts here regarding PM machines (I don't own one so have no personal experience), they seem to be the best for customer service.  Matt doesn't spec out junk components to save a few bucks. 

Bruce


----------



## GTPI (Aug 2, 2020)

BGHansen said:


> Curious what PM has to say about your experiences with this new mill. Replacing spindle bearings on a brand new machine? Reading posts here regarding PM machines (I don't own one so have no personal experience), they seem to be the best for customer service.  Matt doesn't spec out junk components to save a few bucks.
> 
> Bruce


               My mill is up and running after a new motor controller, speed control, new motor and some poorly done electrical connectors replaced.  
      The answer to your question , absolutely nothing, I called last week with a question and was told to ask my questions by email.  I sent the email and got no reply. No follow up to see if the parts worked, nothing.   This board has been much help and I thank everyone here. Times have changed. 
 I know, There's a pandemic !
    Seven week ago I became sick, tested positive for Covid-19, I'm also 64 and lucky have made a full recovery . I'm rethinking what's really important .  Maybe this week I'll make some chips!


----------

