Re: ATM muzzle velocity

["Bob May" <bobmay@nethere.com>]

Trepanning is the process used to cut up glass like this.
If it's optical glass, you really do want to trepan it and get the glass
back out.  Basically, you make a "hole saw" type setup with some steel
flashing (make it nicely round and provide about 2x the thickness of the
glass for working depth) and then start turning it on the glass with some
grit (120-240 is a good grit to use) and water and it will cut through after
a while.  You need to pump the tool up and down a bit to insure that you
keep grit on the cutting face and pressure works the cut faster.  There's a
fair number of people that have described the process on the web so take a
look.
Bob May
http://nav.to/bobmay
bobmay@nethere.com
NEW! http://bobmay.astronomy.net