"steve" wrote in message
oups.com...
Not sure this is the right newgroup to ask but what the heck. I am
working on a project where I need to fasten two small objects together
with precise orientation (.5 degrees). The objects will be taken apart
and put together frequently so the fastener cannot be permanent.

As others have suggested, dowel pins are specifically made for this
appliction.

However, you need to consider who will be assembling/disassembling the
product in question, and whether they're capable of taking the appropriate
care required to not bugger the dowel/hole fit.

While a pair of dowels will allow repeatability within a couple
ten-thousandths of an inch, there is a significant risk that an untrained
operator will incorrectly assemble the joint and (typically) use the dowel
to "shear" its mating hole due to the dowel entering on an angle. Once this
has occured, the hole will require rework to function correctly.

There are ways to minimize the risk. Having the appropirate hole size is
important (precision slide fit as opposed to a light press fit), using a
relieved dowel pin, using one standard pin and one diamond pin, using
hardened bushings instead of soft reamed holes, etc. You pretty much need to
have lubrication every time the dowel is assembled into the hole as the fit
is virtually completely intolerant of corrosion or excessive friction.

The bottom line is that dowels are used extensivly in the tooling industry
and would probably do an excellent job for very little cost in your
application.

HTH.

Regards,

Robin