From: "Bob May" 
To: "atmlist" 
Reply-To: "Bob May" 


The thing that you have to remember is that where you grind on the glass is
where the material is going to be removed.  Doing center over center
strokes with a subdiameter tool means that you spend a lot of time grinding
on the center of the glass so, even tho you are going to the edge, and
past, the mirror isn't going to change too much.  The more correct stroke
is to do a chordal stroke and then blend it in with the COC stroke.  In
other words, a wide W stroke should open the ROC in proper fashion. If you
are alreasy at the ROC that you want, you may want to just start going down
through the grits until you get to the 320 range and check the ROC again
for a final check.  If it isn't moving and you are where you are then you
have developed a stroke that allows for the fining of the surface without
changing the ROC which is a good thing. Bob May
http://nav.to/bobmay
bobmay{at}nethere.com
NEW! http://bobmay.astronomy.net

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