From: "Frank Q" 
To: ,
        
Reply-To: "Frank Q" 



----- Original Message -----
From: 
To: 
Sent: Friday, December 13, 2002 3:24 AM Subject: Re: ATM Splitting thick
mirror blanks


>
> > From: "Frank Q" 
> >
> > Here's my suggestion at splitting the 3" thick blank into 2
x 1.5" thick
> > blanks...
> > Grind a groove around the cylindrical surface of the blank....
> > Put the blank on a grinding table and put a length of thin wire in the
> > groove.
> > The wire should go around about 75% of the circumference - that way the
> > operation takes less time and more importantly, it will cut through the
> > blank
> > exactly where you want.
> > Put some tension on the wire, spin up the grinding machine, feed grit
into
> > the
> > groove, turn off your brain etc etc etc....
> >...Anyhow, that's my suggestion. I can see a few problems with it but
they
> > can be overcome with a little imagination....

> /*****************************************************/

> As you cut with the wire into the glass (while the table is
rotating)...you
> cut a deep groove into the glass.  As the groove gets deeper, you have a
> heavy, unsupported 'shelf' of glass, putting more and more stress on the
> smaller and smaller section of uncut glass.  How do you support the glass
> shelf, while also allowing the glass to rotate?  The wire and 'shelf
support'
> would interfere, no?
>
> As I see it, you may have to keep the glass stationary, and move the wire
or
> other cutting blade in a back/forth motion.  Then you will be able to
support
> the growing 'glass shelf' without interfering with the wire/blade.  Or is
my
> imagination letting me down here?
>
> Tom Krajci
> Tashkent, Uzbekistan

/******************************************************/

The intention is to ROTATE THE GLASS so that the wire grinds its way evenly
towards the centre of the blank. That way you will have a disk supported AT
ITS CENTRE by a cylinder of uncut glass and so it will be balanced.

My GUESS (I say again "GUESS") is that for a 16" blank, when
the central "support" gets down to about an  inch or so, it will
snap cleanly across.

Do you see what I am trying to say ?

I shudder to think how long this operation will take.

PS If I remember correctly, the device used to cut holes in glass is/was
called a "biscuit cutter" (and I have had lots of fun with
those). Maybe we could call the above technique a "cheese cutter"
as it reminded me of the wire contraption found in the kitchen used to cut
cheese !!

Cheers
Frank Q

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