Re: [ATM] Mirror cell ramblings re: thin plate glass3/4-inchx24-inch

["Bob May" <rmay@nethere.com>]

Just pointing out the possibilities.
As to spring steel, guess what your car rides on?  Those springs
are definitely much larger than 18ga.!  Besides, with a large
thin mirror, you're not supporting as much weigth as a full
thickness mirror anyway.
Bob May

rmay at nethere.com
http: slash /nav.to slash bobmay
http: slash /bobmay dot astronomy.net

----- Original Message -----
From: <fundo@bellsouth.net>
To: Bob May <rmay@nethere.com>; <atm@atmlist.net>
Sent: Thursday, May 29, 2008 12:24 AM
Subject: Re: [ATM] Mirror cell ramblings re: thin plate
glass3/4-inchx24-inch


> --- Original message from "Bob May"
<rmay@nethere.com>: --------------
>
>
> > Actually, the triangles in a support system don't need to be
> > rigid!  All they need to do is to be able to support the
weight
> > without bending permanently.  The little fun part of a cell
> > structure is that it conforms to the shape of the mirror back
and
> > provides even support at each point.  If a triangle bends a
> > little under the stress then the positions of the other
triangles
> > in the system just move a little bit to compensate for the
motion
> > of the one triangle.
> > I'd love to make a mirror cell with spring steel just for the
fun
> > of it with basically rigid joints just to show that it is
> > possible.  The compensation of the triangles won't be exactly
> > perfect as springs tend to have the tendency to provide more
> > force as they deform more but for slight movements that
shouldn't
>
> Bob,  The main difficulty I see with this is that non-rigid
components would flex with the changing orientation of the OTA.
This has the potential of causing alignment problems as the loads
change.  Granted, all pieces flex to some extent, but spring
steel isn't generally available in sufficient thicknesses to
support anything but a small mirror (at least my steel manual
states that 18 gauge is the thickest commonly available).
>
> *****-----
> Dan F.
> Memphis, TN
>

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