I turn a fair bit of copper to make electrodes for EDM...

I always use HSS, very sharp, 0 rake angle, mist set so heavy its almost
flood. Hi speed, low feed.

Karl


"Peter Fairbrother" wrote in message
...
Any hints for turning pure copper?

I tried a medium positive rake, very sharp tool, fine feed, and high
speed,
but that broke the tool (and the expensive workpiece) when it dug in, and
a
negative rake doesn't cut, it just rubs (and probably work-hardens too).

Lathe is about as tight as I can get it, overhangs as short as possible.
I'm
turning the soft state, but I could perhaps heat-treat it somehow if that
would help.

I can't work-harden the piece first though. Neither can I use much tool
pressure - it's a diffusion-brazed assembly of thin pieces.


Thanks,


--
Peter Fairbrother