Help diagnosing noise in PM-30MV

J

jwmelvin

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My PM-30MV has something loose in the spindle, and makes what I might call a clacking noise when the quill is anywhere other than fully retracted. When extending the quill, I can see the drive pulley drop a little as the noise begins. Here's a video. The mill is a couple years old, though hasn't had much use at all. I've been using it recently for a project, so it seems that has caused something to loosen or break. PM wasn't able to come up with anything other than suggesting I start taking it apart to investigate, which makes perfect sense to me. I just wonder if someone here has any further suggestions. For now, I'm using the mill with the quill retracted and just cranking the z-axis for everything.

Thanks,
Jason
 
Looks and sounds like your pulley is dropping and hitting the top of your housing. Bolts or screws perhaps ?

If you pop that pulley off it may tell you more.
 
I'm not 100% sure what causes the noise, but after I removed the pulley, I could see that there was some gap between the top bearing and the retaining ring that secures it. There was also paint all over the area, including on the bearing seal and in the retaining-ring groove. I got that all cleaned up, removed the two shims that were between the bearing and the retaining ring, and I can measure that the bearing has an axial gap of about 0.037".

The two shims that were in there between the bearing and the retaining ring were 0.019" total, so it looks like I need a thicker (or additional) shim to take up the space. I think the paint was filling the gap and just recently flaked away enough that the movement could happen.

I wish I had a surface grinder so I could make the shim myself...
 
Were both retaining rings seated in the groves ?
 
Hm. I made a plastic shim to go between the existing metal ones. That eliminated the play that was causing pulley movement, but the noise is still there, somewhere in the quill assembly.

 
I think I figured it out. I removed the spindle and the spindle lock nut (which captures the spindle bearing on the spindle)was loose and just sitting in place.
7c36b1d25760912755ed3807fa8b1c8a.jpg


I cleaned it up, screwed it on, then tightened the two locking screws. Hopefully it stays put.

I don’t know the proper preload procedure for the tapered roller bearings so just tightened the lock nut finger tight against the bearing. Is there a usual procedure based on torque or rotation?
 
Good on you for doing your own thing and finding your problem. Maybe contact PM for the torque.
 
Since your bearings are very broken in, snug it down until you can no longer force any vertical play, and maybe a small twist past that. I think you'll find PM has no torque spec for that. I wonder if you should just replace your bearings while its out..... If that retaining nut was loose, perhaps you had some weird lateral loads on big cuts with that play in quill? Anyway worth it for piece of mind, you can get them on Amazon pretty quick.
 
GunsOfNavarone said:
Since your bearings are very broken in, snug it down until you can no longer force any vertical play, and maybe a small twist past that. I think you'll find PM has no torque spec for that. I wonder if you should just replace your bearings while its out..... If that retaining nut was loose, perhaps you had some weird lateral loads on big cuts with that play in quill? Anyway worth it for piece of mind, you can get them on Amazon pretty quick.
Click to expand...

Well, the machine has at most 5 hours of spindle time. I’d be surprised if that is truly broken in. I didn’t run it much when it was making the noise so I’m betting the bearings are fine. I’ll pay attention to things and maybe run a test when PM sends a new lock nut.
 
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