NavList:

   

Reply

On Sun, 27 Mar 2011 18:49:39 -0700, Bill Morris 
wrote:

> This is an interesting application of the differential screw principle,
> sometimes used in machine tools like surface grinders to make fine
> adjustments. It has also been used in a micrometer head, though not as
> far as I know as a commercial proposition.

I'm very glad you understood my description, and I was actually using the
device as a micrometer head to adjust a front face mirror at the end of
another piece of lath.  I still have the spread sheet with my readings and
various distances to about 500 yards.  I called one turn 0.005 inches, and
had five longitudinal lines drawn on the masking tape.  I could estimate
to approximately 0.0001 that way.

> There are "quick and dirty" ways of tightening a nut around a screw. The
> nut can be split longitudinally and closed up a little in a vice, or it
> can be split tranversely across the full diameter of the thread while
> leaving part of the wall intact and closed up a little in a vice.

That was the effect of the shrinkage of the outer tube on the two ground
off nuts, an axial compression.  I wish I had thought of that *before* it
happened, though.

> A more refined way of closing this latter is to drill and tap for a
> small diameter screw.

Ahh . . . .  My skill is not to that level, but I think I may tighten the
plate-nut by your second method, one or two transverse cuts and judicial
use of a vise, then lap the threads for a smooth fit.  The project has
been abandoned, but I may as well make this improvement for use in a third
design.

Thank you.


--
Richard . . .

Using Opera since the"Dog" died

   

Reply