The message
from Chris Bacon contains these words:

You can drill toughened glass, you just have to be careful
(and very slow), and use a fine abrasive and rod as ?? ago.

You sure about that? As I understand it, once the compressed outer layer
is broached the whole thing goes bang no matter what. Prince Rupert's
Drops and all that.

--
Skipweasel
Pay no attention to that man behind the curtain.