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View Full Version : Knock Knock, what's there?



Bill Schulz
03-19-2021, 2:32 PM
I have a PM3520c I purchased new 10 months ago. It has developed a ticking (knock?) noise in forward rotation. With belt loose, no chuck mounted and hand rotating, the noise is still audible. 1 tick per revolution. Any thoughts on this?
I have a call in to Powermatic. Video here:
https://photos.app.goo.gl/PnW5TDxtjunLbD3B7

Update: First I removed the spindle lock assembly. I loosened all grub screws (all seemed tight) on the upper shaft and moved the pullys and spindle lock/woodruff key around a bit then retightened all the grub screws. Nothing looked amiss at all. I then marked the setting on the castle nut, bent up the tab, and loosened the nut. Using a wood mallet I first tapped the end of the shaft toward the headstock then moved to the chuck end of the shaft and tapped it back toward the headstock. My though was to make sure the big bearing was seated. I then retightened the castle nut to factory setting.

I messed with this about 5 hours and I'm happy to report the clicking sound is gone. I wish I could say exactly what it was that fixed it but I can't. I used the lathe heavily this morning and still no clicking sound. I forgot to mention the the clicking did not occur on the high speed pullys. Go figure.

After going thru this I'm confident I could replace the belt and probably the bearings if required. Hopefully that will be never.

Alex Zeller
03-19-2021, 2:44 PM
While not a Powermatic my Grizzly developed a ticking noise. It was a washer between the bearing and the pulley. All I needed to do was loosen up the set screws on the pulley and push it tight to the bearing and the noise went away. It could be a bad bearing but being so new I doubt it.

Steve Eure
03-19-2021, 2:51 PM
First thought I had was a bearing, but it doesn't do it in reverse. I did notice that every time it ticks, you see a white or shiny spot on the top of the spindle assembly where it meets the bearing housing on the headstock. Don't know if that has any bearing on the problem, but it just seemed peculiar to me.

Bill Schulz
03-19-2021, 3:23 PM
First thought I had was a bearing, but it doesn't do it in reverse. I did notice that every time it ticks, you see a white or shiny spot on the top of the spindle assembly where it meets the bearing housing on the headstock. Don't know if that has any bearing on the problem, but it just seemed peculiar to me.

Thanks for the response Steve. I too noticed that dull spot when I watched the video and after close examination I can't explain it. It is not as polished as the rest but doesn't appear damaged, at least the part that is visible. I'm going to see if I can loosen the pully set screw and maybe tap the shaft to insure it's tight in there.

Best Regards

Bill Schulz
03-19-2021, 3:25 PM
Thank you Alex. I'm going to see if I can do as you suggested. It's rather clumsy in there. ;-)

Best Regards

Richard Coers
03-19-2021, 7:29 PM
Powermatic has a long history of speed sensor coming loose and making the ticking noise. If you Google your lathe ticking, you'll find lots of reading.

Richard Coers
03-19-2021, 7:31 PM
Powermatic has a long history of speed sensor coming loose and making the ticking noise. If you Google your lathe ticking, you'll find lots of reading. https://sawmillcreek.org/showthread.php?84441-clicking-noise-in-headstock-pm3520

Robert D Evans
03-19-2021, 8:33 PM
I don't have a Powermatic but my Grizzly started doing the same thing. I found that the hand wheel on the spindle was loose. Tightened up the set screw and it went away. I hope your solution is as easy.