Machining what am I doing wrong?

Your problem almost certainly stems from the very inadequate top slide clamp which flexes under load. I know this from first hand experience!! Look at Steve Bedaires web site where there are lots of mods to improve these lathes. The 9 x 20 is a very lightly built machine and needs bolting down securely to eliminate bed flexing as well. Once these improvements are made you will have a different machine believe me!

Whilst reading the threads, my first thought was the clamping of the tool post... as Martin has mentioned above, go to the Bedaire website and read his ideas on improving the 920.

I have one of these.. its pretty good for general work, the clamp was the first thing I did to improve stability. I did it on the lathe using the 4-jaw chuck, so you wont need any special equipment.

I'm now reworking the bearing plate for the compound screw, and making a replacement "imperial" leadscrew for it too as mine is not accurate (metric leadscrew with imperial markings).

Tumbler reverse will be on the list of future improvements.

Rgds

del.

Using the BH600G with the VFD has been a revelation for me.

All I do now is twiddle the motor speed knob and select depth of cut to suit rate of traverse.

It was very hit and miss on my V10P, having all too often to resort to manual traverse to get a decent finish.

Even now though, when required, I will wind the saddle backwards manually, either without moving the toolbit or just a division or two inwards on the handwheel, to get a virtual ground finish. Something I learned when using the Emco.

There was an article in one of the magazines about making a special tool to achieve a good finish.

Geoff - No workshop today, just not up to it. Bummer or what!