This is driving me crazy. I've tried everything I can think of.

-Centre height OK.
-Blade not overextended.
-Insert OK
-Coolant on
-Reduced speed, increased feed
-Adjusted backlash on cross slide to minimum
-Saddle clamped
-Happens with different materials, and diameters

But I can't eliminate the vibration. It is really heavy, and is
causing clamping screws and the like to loosen.

It's making me feel like a complete idiot. I should be able to solve
this problem, but what's causing it?

Any suggestions, or should I just go and slash my wrists now?! g

Cheers, Dom.