Re: [CAD_CAM_EDM_DRO] Re: making ball nuts

jmw@... wrote:

> but I doubt it has gothic arch threads. The screw does not; I'm not
> sure about the threads in the punch body. Anyway this unit has been
> working for about 75 years.

I doubt you are much concerned about where the punch is in it's vertical
travel vs the angular position of the lever. Different game entirely.
And yes, I had one of those punches once. Grooves are deeper than
regular ball screw and probably of a slightly larger radius than the
ball.

> Now shaping a toolbit to the arch shape shouldn't be too bad,

Getting the proper shape on the tool is possible with care.
However, consider that as your depth of cut increases, so will the
length of cutting edge engaged in the cut. Unless you have a very
massive boring bar and a rigid lathe, somewhere along the line you are
almost certain to get some significant chatter. Ball bearings don't much
care for running over washboard.

> I don't think hardening would be a real problem.

Hardening won't, avoiding distortion will.

Not trying to discourage you here. I think a home made ball screw that
is smooth and holds up would really be something to be proud of. But I
suspect that if you get that far, you won't be much interested in doing
it again.

Jon