32 mm brass wobbly in chuck

[Ontheblocks]

Seeking advice/critcism re this recently developed problem. I make automata, increasingly using brass for many parts, using a Sieg M1 lathe/mill combo. Trying to make what are simply large 2mm thick washers with a 7/16 hole, which will used to secure ply cams to a crankshaft.
It was impossible to part these off the 60mm long bar due to serious chatter. I have made the same washers recently to fit a 6mm crankshaft, which was unstable under heavy load. That process did not have this problem. The new crankshaft is 7/16, hence the need to remake this part. Naturally, the center hole drilled on the lather prior, is likewise unusable.
The three jaw chuck appears to have one jaw, minutely off center when fully closed, empty. Could this develop, just like that ? Also noticed a ropey appearance to the surface of the bar. I intend to revisit the cross slide settings, but the chuck, can't think what can be done with that, if that is the main problem. The parts I make do not need to be super accurate, only good enough to do the job I make them for.
Any view would be very welcome,

Regards to all,
Gus

 

[MrWhoopee]

It almost sounds like the jaws were removed and replaced in the wrong order.

 

[benmychree]

If the stock revolves without wobble, the problem with the jaws should not cause any problem. The problem may simply be with a lathe that is not rigid enough to withstand the cutting forces or perhaps the cutting tools may be the problem in inducing chatter.

 

[Ontheblocks]

If the stock revolves without wobble, the problem with the jaws should not cause any problem. The problem may simply be with a lathe that is not rigid enough to withstand the cutting forces or perhaps the cutting tools may be the problem in inducing chatter.

Thank you gents for the replies, Did some, as it turned out, long overdue adjustments, removed the jaws, cleaned lubed the parts. Those fixed the problem. Back to its happy little self.
Regards,
Gus