To: atm{at}shore.net
From: "Matthew L. Brown" 
Reply-To: "Matthew L. Brown" 


I'm planning a similar scope.  But the solution is pretty easy.  Have the
parts align using 3 balls fixed to one part drop into 3 radial V grooves in
the other part.  This is called a kinematic coupling, and you can get
*micron* level repeatability from it in metal.

http://pergatory.mit.edu/ajhart/research/mitperg/SMthesis/pdf/chapter2.pdf

The V grooves don't have to be accurately done -- they just have to head
away from each other.

=Matt

>   My thoughts
>are complicated by the fact that I want the "truss" tube to break down
>into two,
>or possibly three, parts for compact storage.  Simple screw connectors would
>have too much uncertaintly in final axial alignment.  Again, the tube
>connection
>has to provide axial alignment, length repeatabilty, and rigidity.

--- BBBS/NT v4.00 MP