From: "Russell Jocoy" 
To: adams{at}rmci.net, atm{at}shore.net
Reply-To: "Russell Jocoy" 






>From: "Harold" 
>Reply-To: "Harold" 
>To: "ATM" 
>Subject: ATM flex mirror spring tension ?
>Date: Tue, 11 Feb 2003 11:14:19 -0700
>
>
>
>    Initially the tension spring on my flex mirror was bottoming out before
>the mirror could flex. I was informed by Alan Adler to try McMaster Carr
>#39588k rated at 496 lbs. per in. with a free length of 2". The new spring
>compresses to about .0.71" before reaching  the required 353 lbs force
>  4.02 lbs per in ) nesessary to flex the 12.5" x 1 1/2" thick mirror.
>When
>turning the spring it takes quite a bit of force to turn the wing nut
>enough
>to compress the spring to the desired 0.71" Im concerned that even one more
>crank on the wing nut and the whole thing will explode. So my question to
>those with more experience at flexing mirrors, is all that resistance a bit
>much for the bond that hold s the mirror/sponge/puller or am i being overly
>concerned?
>
>      To date i have only been able to test on artifical star but so far he
>results look promising. There appears to be no astigmatism and although i
>think something could give way before flexing to proper figure, the inside
>of focus rings are slightly brighter than the outside of focus rings but
>they begin to equal out in appearnce and brightness as i begin to approach
>0.71" spring compression.
>
>   Harold
("atm{at}shore.net")

   Harold, maybe you should be trying to flex a thinner mirror. I would make
sure the outside
of the mirror is secured well enough.
                                                   RUSS
("atm{at}shore.net")

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