Re: ATM Re: PUSHING instead of pulling?

["Bill Kelley" <flex@commspeed.net>]

List correection- Sorry, in note #4 I meant HYPERBOLIC- not parabolic. Mea
culpa-  Bill


>
> Dear list,
> Thomas Simmons wants to flex a slightly(?) hyperbolic mirror by reverse
> flexing it. He has been e-mailing me off list. The problem and subject may
> be of interest to list members and I am posting this reply to the list.
FWIW
> if a mirror is a bit undercorrected or overcorrected a simple flex cell
with
> only a center bolt for push or pull may be an easier fix than re-figuring
> the mirror.
> Regards to all,
> Bill Kelley
>
> Thomas,
> Quite so, it won't hurt to experiment. Some notes:
> 1. Plywood is not a good choice to make a flex cell, it bends along the
> grain.
> 2. I don't believe you intend to use a 3-blob support in your flex cell.
> 3. The edge of the mirror will have to be glued to the pusher ring since
you
> are not pulling down on the mirror.
> 4. You need not bother making a pusher plate. A bolt head attached to the
> center of the mirror and pushed will give you good correction if the
mirror
> is only slightly ?parabolic? Adjust the push while star testing.
>
> Regards- Bill Kelley
>
>
> Subject: Re: PUSHING instead of pulling?
>
>
> >
> > Thanks, Bill, and Roger on the crux of the issue "is it TRULY hyperbolic
> > or just a turned up edge". BTW, it's an F10, and just breathing on this
> > mirror...
> > Currently on a "trendy" plywood disk with 3 silicone globs.
> >
> > Hmmmm, never hurts to experiment, as long as I don't drop the mirror,
eh?
>
>
>
>
>
>