# Pm25mv Quill Maintenance



## wm_crash (Apr 23, 2016)

I'm about to get back to some machining here and had a question about  quill maintenance. I am not sure what kind of maintenance a quill needs. Oil? Grease? Anything?

A few months ago, I was cutting a few rather deep narrow grooves (1/8" wide, about 3/8" deep). I was spinning the end mill pretty fast, and it took quite a while with small cuts. The end mills were getting hot, the collet was getting hot (too hot to touch), and who knows what else was getting hot. And that's why I am asking about quill maintenance.

Thanks in advance to anyone willing to venture an answer.

cheers,
Cosmin


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## wrmiller (Apr 23, 2016)

Pretty sure Matt's new PM25s are dry heads like mine was. I had one of the last plastic-geared PM25s that Matt sold. Not sure it was necessary, but when I converted it to a belt drive I had the quill out and upgraded the spindle bearings to some ABEC 7 bearings and smothered  them with kluber isoflex nbu 15 because I was wanting to run smaller end mills and was sometimes upwards of 4000 rpm. May have been a bit overkill, but never had any problems with overheating.


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## wm_crash (Apr 24, 2016)

Mine came with a belt drive. I haven't done anything to it other than wipe the shipping grease, oil the ways and column, and tram. I will soon have to take apart some of the Y axis mechanism to replace a stuck oil hole, and to install an X axis power feed. Might as well take apart the whole thing and do a thorough cleanup, and upgrade the spindle bearings like you did.

cheers,
Cosmin


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## compsurge (Apr 24, 2016)

How hot is "hot"? Do you have an infrared thermometer? This could be indicative of bearing failure or just normal temperature. If you were cutting with too slow of a feed rate, you could have been absorbing heat rather than ejecting it with the chips.


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## wm_crash (Apr 24, 2016)

All I remember is that the collet and the end of the spindle where the collet goes were too hot to grab. I did not use the infrared thermometer on it. Feed rate was certainly slow. I had already broken a mill. Chips were not ejecting by any means. They were piling up in the groove I was cutting, mixed with the cutting oil I was using.

I have since bought a couple of woodruff cutters for cutting deep narrow grooves. It should go better.

cheers,
Cosmin


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## Shouts (May 24, 2016)

Hey I've had my mill for about 2 months now, its a PM 25 and have about 20 hours on it and like yourself I've gotten it so hot you couldn't touch it. But that was awhile ago I used it this last weekend with no problem milling out some aluminum stock. The spindle makes varying kinds of sound but I did start noticing that in high gear around 2200-2300 rpms sometimes it would fluctuate sometimes between 2250-2300 then start going down to about 1800-1900 and then back up to the set 2250 I had it set at. I'd slow it down for a minute or 2 or even maybe take it to reverse to see if that might clear it up and then it would run fine. Tonight I'm out there just drilling a 3/8 hole in this aluminum and it just started locking up. I stopped so I backed completely out of the work piece and ran it in the air and it did the same thing. So pulled the belt off of it and ran the motor up and down (rpm) no problems there. Then started looking at the spindle and it was not hot but it would turn a couple of revolutions somewhat freely then it would start getting tight, then tighter, then just freeze. Spin it back the other way to unlock it and it would do it in that direction as well. So please is time to replace these bearings or what? Any advice is greatly appreciated.. Steve


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## compsurge (May 24, 2016)

Shouts said:


> Hey I've had my mill for about 2 months now, its a PM 25 and have about 20 hours on it and like yourself I've gotten it so hot you couldn't touch it. But that was awhile ago I used it this last weekend with no problem milling out some aluminum stock. The spindle makes varying kinds of sound but I did start noticing that in high gear around 2200-2300 rpms sometimes it would fluctuate sometimes between 2250-2300 then start going down to about 1800-1900 and then back up to the set 2250 I had it set at. I'd slow it down for a minute or 2 or even maybe take it to reverse to see if that might clear it up and then it would run fine. Tonight I'm out there just drilling a 3/8 hole in this aluminum and it just started locking up. I stopped so I backed completely out of the work piece and ran it in the air and it did the same thing. So pulled the belt off of it and ran the motor up and down (rpm) no problems there. Then started looking at the spindle and it was not hot but it would turn a couple of revolutions somewhat freely then it would start getting tight, then tighter, then just freeze. Spin it back the other way to unlock it and it would do it in that direction as well. So please is time to replace these bearings or what? Any advice is greatly appreciated.. Steve


Sorry to hear that! It sounds like a warranty issue to talk to Matt about. It could be any number of things from a mis-machined or warped spindle cartridge to improperly installed bearings.


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## wm_crash (May 24, 2016)

My PM25 sounds alright and does not lock up or go down in rpm. I've had quite long runs on it so it would have shown up if it were going to happen. My plan is to take it apart and give it a good cleaning, and figure out if I can improve it with better bearings. For now, I am doing some woodworking in the shop, so the mill is well covered to protect it from the dust.

wrmiller, do you remember which bearings you bought for the mill? I'd like to order them so I have them on hand when time comes.

cheers,
Cosmin


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## Shouts (May 27, 2016)

Thanks for the input its really appreciated...Steve


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## T Bredehoft (May 27, 2016)

My IR temp gage has shown about 140º, almost hot enough to burn  your hand, but never any higher than that. Certainly not hot enough to degrade any lubricant.


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## Greebles (Jun 3, 2016)

T Bredehoft said:


> My IR temp gage has shown about 140º, almost hot enough to burn  your hand, but never any higher than that. Certainly not hot enough to degrade any lubricant.



I have a PM-727 and the quill gets VERY hot. Almost too hot to touch. Makes changing collets "fun" as they are just as hot. I have been worried about this because my old X2 mill runs at much higher RPM but stays nice and cool.

-Denzil


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## compsurge (Jun 3, 2016)

How long have you run the bearings in for?


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## T Bredehoft (Jun 3, 2016)

compsurge said:


> How long have you run the bearings in for?



I don't time them, as long as needed. some cuts, milling up to 15"... yeah, the spindle gets hot, but like I said not hot enough destroy the oil.


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## compsurge (Jun 3, 2016)

What I was asking was how long the bearings were broken in.  If they were not broken in sufficiently, it could be part of the issue. It also could be improper preload, a misalignment,  or some other issue.


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