Follow Up:

Lathe is a Kirloskar 400. Geared Head. 400mm Swing. 1000mm Between
centres. 3.7kw (5hp) Approx. 10 years old. Its still in excellent
condition. Hardly any wear in the bed. It isn't bolted down, but
weighs 1200kg. (2640 lbs). I guess if it was bolted down, it might
eliminate some of the vibration.

The chucks we use are a 3 jaw and 4 jaw self centering Tos, and 4 jaw
independant Tos. Same results on all.

Parting tools are Sandvik. Bought a new blade about three months ago.

"This may not be correct, but I found that grinding the cutoff tool
to put a chip-breaker in the top surface solves the problem."

Sandvik tools have chip breaker incorporated into them. Not really
having problems forming a chip.

Could the preload on the spindle bearings need adjustment? I was just
reading the manual, and it does discuss adjusting the preload. I also
seem to be having a little trouble getting a nice finish when facing
off. Axially it seems to be very accurate, better than .01mm and
radially it doesn't seem to be too bad, but the only operations that
apply a radial load are parting and facing.

I haven't tried engaging the cross slide feed, maybe I'll do a test
like this and see what happens. I have noticed that the tool seems to
get pulled in almost as though it is not feeding fast enough. I have
a box with all the crashed and broken tools next to the workshop door
to remind me of my mistakes and keep me honest. There is still some
room in it, so I'll get stuck in and see what happens.

Thanks all for your quick responses.

Dom.