Re: ATM Tool for rough grinding?

["Bill Prewitt" <bprewitt@neo.rr.com>]

A 2 to 3 inch pipe cap will work just fine.
You should file down anything sharp on the lip before you touch glass.

Also be careful and don't get too close to the edge when hogging.
It's easy to pop off a flake from the lip.
The very first thing you do is bevel the lip of the blank to protect it if you
slip.

Hog to maybe 2/3 of your target saggita, and avoid the outer inch.
You need to have enough glass left to sacrifice to get your tiles into contact.
              Good luck with it,
              Bill Prewitt

My webpage of telescope making and caving
http://home.neo.rr.com/imaging

> So what should I do the hogging with?
>
> I'm thinking of finding a 3 inch cast iron pipe end cap to use for my
> hogging tool, this for an 8" mirror.  Would that be a good idea or what
> would you suggest?
>