lemel_man wrote:
Dom wrote:

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.

I had a similar problem on a 5" CH (10" swing) Boxford. In desperation I
eventually tried levering the spindle up and, to my horror, found there
was movement - the bolts holding the headstock to the bed were a little
loose. After tightening the problem went away.
Far fetched? Yes, but you never know...


Somebody obviously had that headstock off in the past. Any looseness,
anywhere in the entire lathe, will show up when parting off. A really
common one on the lighter lathes is lifting up of the carriage off the
bed. You can just drive a toolholder into the side of the chuck or
workpiece with the lathe off (using the crossfeed), and look for a
change in the fillet of oil between the carriage and ways. If you see
it, you want to work on the gibs under the carriage to remove as much
slack as possible. If you can get the carriage to lift off the ways
during a parting-off cut, the vibration will be scary!

Jon