Re: Digest Number 140

Dan Mauch wrote:

> Im always like tricks. Let's hear it.

The natural tendency is to spray perpendicular to the screw.
Even laying it on in what appears to be heavy coats, will likely give
you a nut that is too tight and must be lapped in with Timesavers. You
need to angle the spray to get as square to the sides of the threads as
possible, else the release agent will build up primarily on the crest
and roots.
When the nuts I cast came out so tight I needed pliers to get them
loose, I had to machine a short length of screw stock to fit a collet in
my tapping head. This was placed in my lathe spindle, and after
protecting the ways, I spent a pretty fair amount of time running nuts
back forth lapping them out.
This takes time, as the nuts must be flushed and washed well before you
can really gage the fit.
Even after my first attempt and being advised by Devitt how to apply the
release agent to screws, and really laying it on (or so I thought), the
second try still needed lapping, but not near as much.
Timesavers is a special lapping compound that will not embed, and breaks
down with use.

Also, Moglice will replicate even the smallest of details. Do not even
try to cast a nut on a screw that has burrs, pits, or other roughness.
Use a microscope or strong loupe to examine the core screw. Casting on
precision ground stock is best. Rolled stock is less than perfectly
consistent, and would more likely require lapping.
In the case of the DoAll, I ended up with a nice new screw and nut for
about $1400 less than DoAll wanted for new, so it can be worth the
effort.

Jon