We machine large inco bar stock (6" dia) x 6' long and we always have problems with th bar moving around in the power chuck, we have tried wedges to support the other end of the bar but most times the wedges vibrate out and we end up spending time to stabilize the bar again. We make small seals from this bar stock so we are always moving the stock out for the next seal to be made. Anyone got any ideas for stabilizing the end of the bar? Most times the stock is inside the spindle tube.

spindle liner?

Make bushings that go inside the spindle; OD just a neat fit in the spindle holw, ID just a small clearance on the bar stock. They can be spaced several inches apart with larger ID separater tubes and retained with a flange attached at the far end of the spindle,

Need a quote, eh? How's this:

"Ask not, with whatall shall I shim this contentious bar, but rather, with what shall I adapt my oversize spindle".

:D

Had the same problem years ago on a johnson klob terret, we had to make up a roller bed to support the bar in feed end and a ring with 3 rollers to stablize the end till we fed most of the stock in and machined off what we needed , low RPM's