If one is set on drilling through glass, the brass tube and abrasive compound is probably the best for a small shop.
I used Clover brand valve grinding compound and a brass wire to slice heavy-wall Pyrex tubing many years ago. The abrasive is somewhat self-replenishing (unlike drill bits - when they break, you're done.) Lots of water and renew the abrasive regularly.
Donald.
-------------- Original message ----------------------
From: "Stefan Trethan" <
stefan_trethan@...>
[snip]
> I always wanted to see if a carbide PCB drill will drill through glass
> but never got around to trying it. If you do try, let us know.
>
> One thing to keep in mind when using weird and wonderful PCB materials
> might be that the thermal expansion coefficients may not match those
[snip]