[ATM] RE:Figuring nightmare

["Ellen Mackenzie" <mackenzieconsulting@sympatico.ca>]

Hi Brent;
    Following your thread I am beginning to think that it may be possible
your lap is too hard and your strokes a bit too short. I ran into the same
problem once with a hard lap and too long a stroke  - -resulting in a hole
in the centre. If you are pressing every 15-20 minutes you are not allowing
your materials to rest long enough to stabilize. Also you should have an
extremely wet lap with a bit of dishwashing detergent added to hold your
polishing materials in suspension and keep the interface cool.( teaspoon per
quart of water )
On a previous list it was mentioned that a stabilizing time of an hour
resulted in a different figure, slow down and give it some time. Also watch
for the heat transfer from your hands unless you are wearing insulated
gloves. If you have been pressing in the center with bare hands this will
create a hole as well.
	A full W pattern while rotating the mirror and moving around the lap
tends to negate irregularities devolved by working the lap in one position.
Remember the lap changes as well as the mirror.
	To get back to a sphere limit your over hang to less than 20 %
diameter.


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