Tim Wescott wrote:
I'm looking for product names to look for.

I'm working on an instrument for a customer, and he's having me do the
whole-system design. This means I'm out of my comfort zone and playing
with mechanical issues.

It needs a big outer case (well, four feet long, by nine inches by two).
I'm thinking of doing the outer case from fiberglass for a number of
reasons, not least of which because I'm familiar with its
characteristics, and the instrument is going to be used on or near bodies
of water including salt water.

I'll need to attach things to this outer case. My current thinking is to
used buried studs and/or nuts, and use thumb-nuts and thumb-screws to
actually attach the bits. I'm assuming I want to use brass or stainless
hardware for corrosion resistance, and I probably want to take some pains
to match alloys.

McMaster is failing me for appropriate hardware. I'm finding thumbscrews
and thumb-nuts, but I'm not coming up with good candidates for nuts that
I can bury in the fiberglass. I'm assuming that the case will be a two-
part assembly that's glued together; nuts that can be buried in one side
and then captured in the gluing-up process seem to be the best notion to
me, but if someone with actual experience has alternate suggestions, I'll
listen (I may not _take_ your suggestion, but I'll certainly _listen_ and
_think_ about it).

So -- suggestions? I'm probably wanting some 4-40 or 6-32-ish sized
ones, and some 10-24 (or 1/4-20). The bigger ones may work better as
studs, with thumb nuts. I'm pretty sure that I want nuts for the little
ones, unless that presents severe difficulties.


Depending on how thick this case needs to be you might want to think of
a composite construction. Use something like thin plywood for a core and
install either stainless nut-serts or T nuts into that panel, then use
marine grade epoxy and glass mat to make it waterproof. The wood gives
you some structural strength and will hold the inserts in position.
Don't forget to insert the proper screws coated with release agent so
that the threads are clean.
Another option would be to install the insert into a piece of expanded
stainless sheet and embed that. That would give you more surface area.
Probably not needed with the little fasteners but might be for the
larger ones.

And lastly, If this will be a continuing item, you could take a piece of
stainless and make a girdle that has the holes drilled/tapped in the
correct places and glass that in.

Now that you've asked this bunch, Try dropping a note to Randy at
gofastfiberglass AT comcast DOT net He builds 'glass scoops, body
parts and more for some of the fastest vehicles out there. He can
probably give you a better idea.

--
Steve W.