Re: [ATM] Back to original "ball bearing for triangles" thread?

[Rocky <wb5ftr@zianet.com>]

Raphael,
At 08:56 AM 9/5/2004, you wrote:

>What's bother me is that my pivot point in my big triangles doesn't rotate
>well, certainly because
>1 the conical mill i've done to the bottom part of the triangle is not well
>done
>2 the accorn nut i've in my pivot point has a small "shoulder"  that could
>bother the rotation, see the picture
>http://www.atmlist.net/contrib/rguinamard-at-infonie-dot-fr/600f3.3/triangles%20inf%2brotule1.JPG
>So my big triangle is not horizontal and to put it horizontal, you have to
>provide a force .
>See for example the weight I have put as a test :
>http://www.atmlist.net/contrib/rguinamard-at-infonie-dot-fr/600f3.3/triangles%20inf+contrepoid%201.JPG
>I think this force necessary to put the triangle in the same plane as others
>could deform my mirror.

If the center of your pads correspond to the "points" specified in PLOP, 
you are on the right track.
I printed out the pictures you had in the links, and drew triangles 
relative to the center of each
circular pad.  The pivot in the middle of the triangles is where it should 
be.  If you spin the large
triangle 180 degrees without moving the acorn nut,  does the tilt of the 
large triangle change
relative to the rest of the triangles?  For example if the point of the 
large triangle becomes the low
end, then you might try "smoothing" the acorn nut to get a more level 
configuration.  But if the point stays high, I would suspect a problem with 
the "conical" at the pivot hole.

Clear skies,
Rocky

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