Shimming Techniques

Suggest it's the spindle bearings.

Tony

You mean axial play effectively, or radial as well?

I've put a bar in a chuck in pulled it backwards and forwards and cant feel anything. Not put a clock on it though, apart from checking runout which was OK.

Seems likely, but I'll have to do a much more in depth check. There's certainly nothing 'loose'.

There was no play in these bearings that could be felt by hand - before & after adjustment, using same cutter & set-up..

It'd be perfectly normal to have to adjust the spindle bearings after a period of running as the cycles of heating / cooling, vibration and pressure settles the components into place against each other, and the initial cold setting made at the factory is lost..

Maybe someone (with knowledge of the SX?) could explain the 'how to'? ..I'm gonna be really late for work

I can detect no axial or radial play in the spindle at all, so the side milling problem remains a mystery.

Looks like an impression of the helix on the flute of the end mill.

One assumes that everything is rigid, cutter tightly clamped, cutter holder firmly clamped into quill, minimal backlash in fedscrew, (nip up the clamp ) work holding rigid?

A lower feed rate, and shallower cut, might help?

Having said that, sometimes a heavier cut stabilises the cutter

Howard

A pattern like that means a resonance is being set up between the cutter and work.

The movement may be undetectable, but the resonance means more movement than usual.

A small speed change should prevent it, if it is aesthetically undesirable.

Neil