Turning Archive 2006

PM 3520A Concern (a little long)

Black Bear
>A couple weeks ago, my PM 3520 A started to make a clicking sound inside the headstock. The sound is tied to spindle speed (one click per spindle revolution). I am a former product support engineer so I did your basic diagnostic evaluation. It is louder when I really tighten the drive belt by pushing down on the motor mount lock. No additional heating in the headstock casting at either bearing location. All screws are properly set and all pullies are aligned. Louder when I have an out of round bowl blank than doing a spindle or a once-turned rough bowl.

Thought I had contact problems between the locking pin and the spindle lock collar. Actually pulled the locking pin out and still had the noise.

Thought I had a flat spot on the belt but after multiple repositioning of the belt, still had the noise.

Went to Louisville and asked "Barry" at the Jet Powermatic booth about it. He said he thought my set screws on the spindle pulley had backed out and the clicking (which happens somewhere as the spindle key goes over the top from about the 3 to 6 on the clock). I removed the set screws, and then retightened starting with the set screw on the spindle key. Also did the same thing with the spindle lock collar. Really put a good torque on the set screws. Still had the noise.

I am frustrated as I pride myself on taking good care of my tools. I have mostly built my shop on rebuilding tools I bought second hand but this one I coughed up the full new price just 8 months ago.

Any ideas?

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