[ATM] Thinking while parabolizing

[bobmay at nethere.com (Bob May)]

The figuring process is a very dynamic process.  You are right in that you
are getting a bit of sticking near the center of the stroke and this is
indeed from the vacuum that you are forming if you don't have grooves in
your lap.  I'll note that the stroke that makes the parabola is actually
cutting material away from the center of the mirror with the wide W stroke
and you need to check often to insure that the curve is coming in even and
smooth as it is quite possible to dig  a center and not get that out to the
edge if you go too wide and long.
Bob May
http://nav.to/bobmay
bobmay@nethere.com
NEW! http://bobmay.astronomy.net