Re: ATM Rough ground to edge; not a sphere, what next?

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

You're not going to be able to get much more spherical with the 80 grit.  It
is now time to start down through the grits.
You will find as you grind, the ROC will change. make sure that you keep a
good track of it as you grind and you really want to be a little long when
you start the last grit so that you can spend the time making it spherical
rather than keeping to the ROC that you want.  Everytime that you change the
tool and mirror, there is a period of time when the shape goes away from
spherical until the grinding has gone far enough.  The last grit can easily
change the ROC by 3-5" if you allow it to.
Bob May
http://nav.to/bobmay
bobmay@nethere.com
NEW! http://bobmay.astronomy.net