Re: [ATM] ?Glued Mirror Cell

["Jan and Rod Shea" <jnrshea@comcast.net>]

Tom,

I'd love to see pictures, but if it is too much trouble, I think I get the 
idea well enough from your description.  The nylon washer sounds like a good 
idea, I built an 8" 3 point cell ( mirror glued to ApplePly, bolts glued 
into holes through the plywood) with a similar mechanism, but I think I will 
add washers to the collimation bolts for more smoothness.  I will look into 
Cell Parts as well, to draw patterns for the bars.  Printing out templates, 
spraymenting them to blanks, then cutting the blanks has worked well for me 
in the past, and I will probably do it with this scope also.

Thanks,

Rod


----- Original Message ----- 
From: "Thomas A Simmons" <tasimmons@raytheon.com>
To: <atm@atmlist.net>
Sent: Wednesday, September 15, 2004 7:33 AM
Subject: Re: [ATM] ?Glued Mirror Cell


>
>
>
>
> Hi Jan and Rod,
>
>  Richard told me NEVER to reveal his magic, but since you let the
> cat out of the bag, it was his patent and a few off list messages
> that inspired this cell. I didn't follow his recipe on the collimation
> bolt, as the off-the-shelf screw didn't require soldering and all that.
> Simplicity at it's finest!
>
>  You asked
>
> "Do I understand that you made the collimation bolt - bar
> pivot point by basically countersinking the mirror side of the hole
> through the bar, and RTV'ing the ? flathead machine screw into the
> hole by gluing the screwhead into the countersink?"
>
> Yep. I don't remember the screw type, but it was a 5/16 screw with a
> 3/4 inch or so flat top and perhaps a 135 degree champher underneath.
>
> You then wrote
> "Seems like you could back it up by putting a locknut on the
> underside of the bar spaced a little way back, and glued to the bar
> as well."
>
> Weeeellll, this is un-necessary. In sequence from the bar I have a flat
> washer, followed by a spring, another flat washer, the bottom of the
> mirror box, a nylon washer and then a wing nut. The spring came from
> MSC and is rated for ~30 lbs. The first springs I used were too soft,
> and allowed the mirror to shift somewhat. The nylon washer under the
> wingnut allows very smooth adjustments with low resistance.
>
> I believe you mentioned Tom Kracji's web page, which goes in debth into
> Richards patent and cell design. All I can tell you is that it works
> very well with this 25 pound mirror.  Maybe $5 in parts?
>
> Another tip. I believe Mark Holm is the author of "Cell Parts". I used
> this program to print out paper templates, thus simplifying the task
> of assuring the three bars were identical and the holes were properly
> positioned. (Ellen was mentioning something along this line the other day)
> With a little creativity, you can also set the Foucault reduction programs
> to print out a mask that will have the proper radii for the attachment
> points-set the mask opening to be VERY wide and VERY narrow.
>
> I'll try to pull the mirror out of the scope this weekend and snap a
> picture of the back of the mirror showing the cell.
>
> Tom
> Tucson, AZ
>
> _______________________________________________
> ATM mailing list http://www.atmlist.net/
> 


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