In article 1119301033.308925.119370
@g47g2000cwa.googlegroups.com,
says...
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.
Currently I am using a plain screw fastener which I have to calibrate
each time I fasten them together, (by lining up guides on each object).
I desire something more idiot proof and more accurate, I was thinking
maybe a bayonet type mount thats used on camera lens would work, since
they lock in at a fixed position. But maybe I'm thinking too complex,
haven't had any luck searching google because I'm not sure what to
search for, so if someone could give me some ideas where to look that
would be great!

steve



The classical solution to eliminate all 6 degrees of
freedom (3 linear, 3 rotational), without redundant
constraints, is one each of a sphere/plane mate,
sphere/cone mate and cylinder/slot mate. Google "kinematic
mount" for more details.

If you already have two surfaces clamped together, and only
need to minimize relative rotation, two pins in a slot is
easy.

If you need accurate linear location as well, think about
two pins in cylindrical holes, or one hole and one slot.
You can loosen up the accuracy required in making the parts
by the judicious use of "diamond pins." For example...
http://www.carrlane.com/Catalog/inde...825071F0B22111
8070C1C513E111D081B0006280B1713050245221E0107070F1 A3C3B2853
56415F

Here's a high-tech solution...
http://www.g2-engineering.com/spherolinder.html

Ned Simmons