Re: [ATM] lap plowing

[John Moore <jamoore42@yahoo.com>]

Hi Chuck,
 
First off, if the lap is digging as bad as you say, do
a lap-hardness test, sounds like its too-soft,
are your channals holding up?
how often do you have to trim?
what are the current readings knife-edge Readings?
what is the room Temp. and do you 
try to stay in a 1-5deg. environment shop-temp?
are you polishing in the temp, needed for
that lap-hardness?
Whats the humidity Like in the room?
Put the tool&mirror in a bucket of room-temp water,
to help them to stabilize, before you begin to Polish.
try switching to 1/4 strokes,, its hard sometime, especially
on a 6inch to judge a 1/3, or even a 1/4 stroke, but just
try to think in smaller terms of the stroke.
Dont wory about the center, it will come-in-line
after a while, Your biggest worry is the edge!,,
guard-it well,.
 
see what others come-up with also!
 
Good-Luck!   John Moore.
              ----------------------------------------------------------------------

Chuck Meaney <chuckmean1@sbcglobal.net> wrote:
Can you help me someone?

I am figuring a 6" mirror with the lap on top to
reduce a central hole- and while using a 1/3rd stroke
after cold pressing for 1 hr, you can even feel the
lap plowing into the edge of the mirror. The Foucault
results have been a slight turning at the extreme
edge. Lost the diffraction all the way around the
mirror, and now very bright on right. The lap is
trimmed well, and conforms to the shape of the mirror.
What am I doing wrong?

Chucko




_______________________________________________
ATM mailing list http://www.atmlist.net/




__________________________________________________
Do You Yahoo!?
Tired of spam?  Yahoo! Mail has the best spam protection around 
http://mail.yahoo.com 
_______________________________________________
ATM mailing list http://www.atmlist.net/