Re: Acme / Ball Screw conversion

OK... Jon, Ray and Ballendo!

Now I would have never thought of the compressive thing, even though
I've seen the tables in the catalogs.
Just goes to show, it never hurts to ask the experts.

Now that I'm scared straight.
I think it is probably best to save this screw for my little lathe,
and wait for the opportunity to finagle a 3/4" setup.
I don't think I have room for much larger.

Actually I am using step motor drives and I have retrofitted the Y-
axis with a 1" ball screw.
You see, a bit here and a bit there.

I opened my Danaher Linear catalog to the "Compression Load" Table
and let my finger do some calculating.
A 1/2" x 30" screw with my Ball Nut and Rigid Mount on both ends ~=
1500 lbs. Max. Compression Load.
A 3/4" ~= 7000 lb. Max. Compression Load.
A 3/4" screw, with Rigid Mount on one end only ~= 3000 lbs.
I would guess that using tension such as Jon suggested, the tension
amount would be directly added to the above loads.
These numbers look really good to me, or because of my empirical
nature, actually don't mean a heck of a lot either.

Is 1000 lb load on a small mill considered norm?
So what do you think?
Would you consider a 3/4" screw to still be on the flimsy side?

Tom M.