Gunner Asch wrote:

On Tue, 17 May 2011 10:03:25 -0500, "Pete C."
wrote:


"Lloyd E. Sponenburgh" wrote:

The precision of rolled screws just leaves me
cold -- 0.003" per foot is crazy sloppy.

Don't forget that CNC controls include screw mapping / pitch error
compensation. Measure and map the screw once and all the inaccuracy is
gone for good, or at least until you wear out the screw. Commercial
machines / controls use screw mapping as well.

True indeed.

Others, such as OmniTurn..use high quality ballscrews and dont have to
worry about screw mapping.

I worked on some very high quality machines back when I did CNC service,
and *all* of them did screw mapping. Replacement ball screws came with
pitch error tables to enter into the (Fanuc) controls.