Pm 3520c headstock not locking solid

[Dean Center]

Looks like the problem is the bottom of the headstock was not quite flat. It was slightly convex. Less than a .0015 shim. I filed down the center portion a bit and the vibration is greatly reduced. I need to file it a bit more to get it perfect.

For the tool rest clamp, I added a spring between the two clamp blocks to push them apart. This eliminated needing to fuss with it when changing tool results.

Glad to hear you figured it out and have a straightforward solution.

Nice hack to put a spring in the tool rest clamp. That's something they should want to include in the "D", if it ever comes out. Maybe they'll give you a hat in return for the suggestion.

 

[Bill Boehme]

I don't know anything about this lathe or its clamping mechanism. But my first thought is to try and slip a shim between the bed and the headstock at one end when the clamp is fully loosened. Even a layer or two of paper might be enough.

Ordinarily, that might be a good suggestion, but unfortunately on the PM 3520 lathes the motor is cantilevered out the outboard end of the headstock.

If I am not mistaken, I believe there is an adjustment on the handwheel end of the spindle that might need to be snugged up a bit to remove any free play. You might need to remove the handwheel to access the spindle bearing lock nut. Straighten any bent tabs on the lock washer. Don't over-tighten the nut. Never mind, I see that the problem has been identified and corrected.