RE: ATM rounding the edge

["Russell Jocoy" <russjocoy@hotmail.com>]

>From: Ina Ron Lippard Renaissance Reproductions <renrepro@surfglobal.net>
>Reply-To: Ina Ron Lippard Renaissance Reproductions 
><renrepro@surfglobal.net>
>To: <atm@shore.net>
>Subject: ATM rounding the edge
>Date: Tue, 06 Jan 2004 07:51:48 -0500
>
>
>
>    Dear List,
>   There is a way to true up a mirror blank before you begin to grind 
>it.Take it to a stone shop that deals with granite. They have equipment 
>that will round out your glass.Failing that,try this.Go to Braxton and 
>Bragg online. They sell 1/2" straight line diamond router bits for rough 
>edging. Coupled with a 'rub-collar' you can rig up a template that you glue 
>to the blank.A piece of 1/2 pine the right OD will work.With a trickle of 
>water running over the blank,use your router to finish up what the glass 
>foundry missed.Take light cuts until you have a nice even machined surface 
>to the blanks edge.The blank will be nice and round if you circle-cut it 
>using a pin and board arrangement on a table saw.Or the same rig that turns 
>under your router. Block up the router so the wood passes underneath the 
>base. Lower the bit for each  pass until you complete the template.
>good luck,Ron
>
>("atm@shore.net")


   Ron, This  is really great to have a perfectly round piece of glass, (if 
you are figuring clear see through
optic's)  Maybe that's to basic of a statement, refractive optic's need to 
be rounded out to definite
guidelines much more that "reflective" optic's.     The grinding process of 
making a sphere on the
surface of glass will produce it's own "round". As Bob May listed recently , 
you can make a nice sphere
from a circle of glass with cut off sides. I think that you glass should be 
round, but to grind the sides
til it plays on a record turntable is going overboard.  The natural grinding 
process that produces a
sphere rounds out itself on the surface if you are following the correct 
process of mirror grinding.
             No big deal, just  thinking that it is more cosmetic than 
necessary..   Russ Jocoy..
("atm@shore.net")

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