Re: ATM Series of Ronchi pics

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

Jerry, if the pitch is moving that fast, you need to either boil it some
more or, better yet, go inside where it is air conditioned and work there.
A cold press shouldn't move the channels hardly at all.  In addition, soft
pitch is just not a nice thing to work with.  It tends to work harden in
places and that makes for a very uneven work on the glass with all kinds of
strangeness happening.
In addition, most people put their hands side by side on the mirror in order
to push it around.  Try putting the hands one in front of the other and
pushing with the near hand and pulling with the far hand.  I've found that
teaching this stroke to the guys usually makes the mirror respond a lot
better to problems that they are having with TDE.  I also have them do a
stroke where the mirror goes from 1/3 towards you to center and stop and
pull it back.  The force goes on the overhung edge and the work of the tool
cuts the high ridge out near the edge of the surface down to the height of
the TDE part of the edge.  Sometimes a flat zone appears in the center from
this but that is taken care of very fast by some spherical strokes of about
1/4 COC.
Bob May
http://nav.to/bobmay
bobmay@nethere.com
NEW! http://bobmay.astronomy.net