On Tue, 17 May 2011 10:09:27 -0500, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

"Pete C." fired this volley in news:4dd28edf$0
:


"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.


Yes, true enough, but the one thing I don't have is the gear to measure
that over 30-some inches of carriage travel. On the one hand, the
hardware would be cheaper, on the gripping hand (using precision screws),
I wouldn't need the instruments (I can live with a thou. over three
feet). Maybe I could get someone who does have the tools to come do the
mapping...

Hmm, that's right. You'd need some sort of feedback (DRO?) to do the
mapping, wooncha?

--
It could probably be shown by facts and figures that there is no
distinctively native American criminal class except Congress.
-- Mark Twain