Re: [CAD_CAM_EDM_DRO] Machinig Ball Screws

In a message dated 03-Nov-01 12:15:43 Central Standard Time, currinh@...
writes:

> I understand hardened ball screws can be machined using carbide tooling.
> I am planning to do this for a rough cut. I'm then planning to use a
> tool post grinder for finishing. For those who've done this, does this
> procedure make sense?
>
> I have not used a tool post grinder but it seems like a good thing to
> have around

Hugh: I don't know what "professional" machinists think of turning hardened
("HSS"???) steel with carbide, but it CAN be done, and rather nicely, if one
uses experience and care. It might be "hard" on the inserts, but, hey,
that's what they are FOR!

I imagine most ball-screws are "case-hardened"; Rockwell 55 or harder only
"around the threads", but NOT down into the center of the shaft. Thus, once
you have the threads turned away, the rest is maybe like turning normal 4140,
etc. I know the Thomson case-hardened "Class-L" way-shafts are "HSS" on the
O.D., but a carbide insert will "turn that 0.1" off (fireworks!), and the
"core" is machineable. May sacrifice an edge on an insert, but they can be
rotated to a new edge, or replaced, cheaper than "heat-treating", and fixing,
afterwards!

Tool-post grinder? Needed one. WOW, those must be made by Jaguar or
Mercedes! So, I got a Graingers ball-bearing DC motor (so it can be made
reversible with ease), and did a little "fixture-makin' ", and lo! A
home-brew for maybe $100 (oh, not "diamond" wheel, and "surplus", but new.
Dayton DC motor). Ya jus' gotta be CREATIVE!

Lotsa luck! Jan Rowland, Troll


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