[ATM] Ball bearing for triangles

[Raphaël GUINAMARD <rguinamard@infonie.fr>]

First of all, I apologie for my poor technical english...

I have a 24" f/3.3 dob.
My mirror is very fine (40mm) an I have built a 27 point mirror cell (9
small triangles on 3 big triangles).
For the "rotation" of the big triangles I have used a carriage bolt that I
have drilled so that the collimation bolt could pass though, and I have
beveled the bottom part of my triangle so that the spherical part of the
bolt could fit in it.
I have put only a very very small amount of grease.
My big triangles are quite heavy (6 mm stainless steel) and my problem is
that there is friction and my triangles needs each approx 300 g of  force to
be really in the same plane.
I think this could deform a little bit my miror because I see some spherical
aberration in the star test.
My question : does anyone has example of using bearing to support the big
triangle (close picture, reference where I could find the bearings) ?
I've seen Bruce Sayre page
(http://www.foothill.net/~sayre/22-in.%20binocular.htm) but I can't get in
touch with him to have more details .
Thanks for your help

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