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Equipment Discussions >> ATM, Optics and DIY Forum

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jonathanCR
sage


Reged: 07/02/07

Loc: Costa Rica
3/16” x 1 ½” Side Rails instead of ¼” x 1 ¼”? new
      #5716739 - 03/06/13 04:07 PM

The K&B book recommends using ¼” x 1 ¼” steel side rails for an 18 points mirror cell (for 16” mirror) but I only have access to some scraps of 3/16” x 1 ½”. Do you think the stiffness or the strength of the mirror cell would be compromised by using these?

Regards


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starman345
Wait, I'm Thinking
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Reged: 07/06/10

Loc: New Brunswick, Canada
Re: 3/16” x 1 ½” Side Rails instead of ¼” x 1 ¼”? new [Re: jonathanCR]
      #5717226 - 03/06/13 08:33 PM

I would use it if that is all you have. I can't imagine it would have a negative impact on your build. You are going to have your cell welded together?

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Pinbout
Postmaster
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Reged: 02/22/10

Loc: nj
Re: 3/16” x 1 ½” Side Rails instead of ¼” x 1 ¼”? new [Re: jonathanCR]
      #5717481 - 03/06/13 10:53 PM

Is it cold drawn or hot rolled?

Online metals.com sells 1018 cold drawn flat bar and the square tubing really cheaply and they'll cut it for you too fairly accurately

I like thicker cause of weight.

But the strength of the 3/16 is fine


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Happy Birthday Achernar
Postmaster
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Reged: 02/25/06

Loc: Mobile, Alabama, USA
Re: 3/16” x 1 ½” Side Rails instead of ¼” x 1 ¼”? [Re: jonathanCR]
      #5717971 - 03/07/13 09:25 AM

I'm sure that will be fine, since the flatbar is 1/4" wider. When welded it will be more than strong enough, I made some brackets out of the same size and type of steel as the mirror cell in my scope that are supporting hundreds of pounds. I am not near as good a welder as other folks, but when I weld mild steel, the welds don't break even when the metal is subjected to being crushed or bent like a bobby pin. If you wish to use high strength steel, make sure to use the right rod or wire. High carbon and alloy steels often require pre-heating to weld without cracks forming in the welds. I's personally just use mild steel, and a 70,000 psi tensile strengh rod or wire suited to it. That way, the welds will be stonger than the base metal itself.

Taras


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