RE: re:Moglice Problem - Fixed?

Kevin,

Thank you for your clear thinking. I got it wrong.

The point I was trying to make is that you want to preserve the lead
of your screw. As Kevin correctly points out, the wear is mostly on
the flanks. In regions of high wear on a machine tool, this is
unlikely to be consistant. Casting over this area will then lead to
binding and errors in the "driven" direction. Using the "new" part of
the thread fixes this. Like most other things in CNC, we have to find
the best of two conflicting needs.

For a definitive answer to this, I called the experts at both Philly
resins and Devitt(moglice). Tough to get people on a friday afternoon.

Bruce Shipley(philly technical ) said to talk to another man with
more "practical" experience; who was unavailalbe 'til monday. I'll
share the results as soon as I get them.

Drew Devitt (technical for moglice) Said, "DEFINITELY cast over the
good part of the screw". When pressed by me, he alluded to the
difficulty of getting the nut off the screw,if done in the worn area.
I then mentioned Kevins idea of USING the screw to split the nut
(after slitting), and using something "springy" to hold the parts
together. After thinking it over, he concluded that would work with
moglice.

Then he added, "If the screw is that worn, you really should chase
the threads to get back to a consistant lead, THEN mold the nut(he
mentioned .0002 clearance for nuts as possible and useful)and
dispense with the "compensating" strategies.

Chief among the advantages of moglice over turcite(someone in this
thread mentioned just use commercially avail. turcite nuts) is the
increased surface hardness of moglice which prevents chips from
embedding in the nut and wearing out the screw. The moglice nut would
wear out instead. Also a higher PV(ability to handle the pressures of
the job :-))for moglice.

Hope this helps.

Ballendo

P.S.Kevin, I like the idea of a "collet" style nut. Since we're
already using polymers, maybe we could encase IT within castable
urethane for the "springy-ness".

>If you want to get fancy you can split it collet-style: 8 splits,
>each one 3/4 of the length, alternating from either end of the nut!
>-Kevin Martin