Best way to machine ball screws?

[Jonathan]

Thanks,

I think they are Chinese, they are branded Gten. Definitely not top quality whatever they are?

I recently machined some Gten 15mm ballscrews ... they were a nightmare compared to the standard Chinese (RM1610, RM1204 etc) ones I've done. The metal was still very hard at 12mm, so no chance of getting anything like a good enough tolerance/finish to fit a bearing unless you have a cylindrical grinder as John S suggested. Instead I just annealed the ends of the screws using the wet rag technique to limit how much is annealed, then it was easy. I didn't want to go down the putting bar into the ends of the screws since these ballcsrews were going to be put in tension - not sure if they'd hold up to that?

This is what it turned out like: