On Sep 6, 8:51*pm, "DoN. Nichols" wrote:

1) * * *Was it truly necessary to anneal the ends of the screws? *I
* * * * believe that they are only case hardened, so after a first
* * * * heavy cut to get under the case, you should be fine. *(Perhaps
* * * * with the insert tooling you were using, you could not take that
* * * * heavy a cut. *I've used that style of insert tooling, and have
* * * * long since abandoned them for the more industrial style with a
* * * * carbide anvil under the inserts among other things.


The ballscrew manufacturer (Roton) recommends annealing for easier
machining. Some posts recommend grinding off the hardened layer with a
grinder (heaven forbid) and those with better carbide tooling
recommend the same as you did. Interestingly, one fellow posted that a
machine shop he approached declined to take on the job for lack of the
proper tooling.

Agreed, those little triangle carbide inserts suck even for normal
steel. Hardened steel would probably kill them in an instant. They're
fine for alu, brass and soft metals IMO. Furthermore, my parting
blades are all HSS so annealing it was. No biggie, I had the
Benzomatic already (plumbing repairs).


2) * * *Looking at the photo showing the teeth of the chuck jaw lining
* * * * up with and resting on the crests of the ball screw thread, I
* * * * suspect that the other two chuck jaws would be touching at
* * * * non-optimum places, so what I would probably do (if I did not
* * * * have collets large enough for the task), I would have taken some
* * * * aluminum, mounted it in the chuck and marked the point in the
* * * * middle of the #1 jaw, then bored it to barely clear the ball
* * * * screw, then removed it from the chuck and slit it at a point
* * * * midway between two chuck jaws (probably 180 degrees opposite the
* * * * marking for the #1 jaw), then put it back in the chuck (using
* * * * the mark to put it in the same position), so it would act as a
* * * * reasonable collet and be less likely to damage the crests or
* * * * flanks of the ball threads.


Several posts on this too. Some recommend using collets and others
recommend filling the grooves with aluminum or copper wire then treat
the ballscrew as a normal shaft. I simply positioned the ballscrew
carefully and had no runout or slipping issues even when using the
die.

* * * * Good job, anyway.

Thanks! And thanks for the advice. I really need to upgrade my lathe
tooling.