"Gene Kearns" wrote in message
news
On 20 Jan 2005 19:17:36 GMT, Dave Hinz wrote:


Two - How could one measure the thread to thread distance accurately to
see
how much error was created when reindexing after moving? Looks like
thread
micrometers only measure the diameter.

I'm interested in the answers you'll get to this. What kind of
accuracy are you looking for?

Assuming you don't have every precision measuring tool known to man...
use what you've got of known (or best) accuracy... in this case, the
lead screw and a dial indicator.

Since a thread is nothing more than a v-groove, it shouldn't be all
that difficult to devise a measuring tool that uses a small round
feeler ( flat sides and round bottom would be easier to use with the
indicator) riding in the cut groove. You are looking for horizontal
displacement as you ride from "old" cut to "new" cut. With patience
and a ten-thousandths indicator, you are probably going to get closer
in that short distance than the lead screw is in a foot.....

So if I clamp a nut to my steel surface plate and then mount the dial
indicator nearby so it rides in the thread groove I should be able to rotate
the screw with consistent pressure against the nut to remove backlash and
detect variations. Cool.

Steve.