Quote Originally Posted by komatias View Post
it depends on your lathe's power. I have machined ends on my little chester using carbide tipped tool

You do need to take a deep cut starting at the face of the screw. It will glow red and so keep a fire extinguisher handy.
My lathe is a Chester DB7 - I think the power is probably ok but would be concerned about the rigidity in trying to hog out a hardened ballscrew with a carbide tip. The other problem I see arising is that I have 12x4 ballscrews, which have a root diameter of pretty close to 10mm, and I need to turn them down to 10mm, so I'm never going to get through the hardened section into the soft stuff below, so even carbide turning on a rigid lathe would produce a pretty rough finish

On reading the previous thread on this subject (http://www.mycncuk.com/threads/2057-...ne-ball-screws), it seems to me that I have two viable alternatives.
1. get them ground down with a cylindrical grinder (but that still leaves me with having to get a m8 thread onto the end), and would probably cost a fair bit.
2. drill into the softer core (which I have found that I can do) and shrink fit or loctite an extension which I can them machine to suit

I'm not too keen on trying the annealing route without knowing what type of steel I'm dealing with, though I may try it on a sacrificial end. One ballscrew I got is about 80 mm longer than I need so if I mess up just the tip I can cut it off and try again

I'll have a go this evening and see what happens