On 2008-12-15 14:30:11 -0800, spaco said:

We had a job recently to install plexiglas shields over a forged steel
gate/railing to keep people from reaching through the ballisters and
unlocking the gate. We'd have to drill many holes in 3'8" thick
plexiglas, on-site, to mount the several pieces that had been
professionally precut to various shapes. Not a good place to fail.
Having had some bad previous experiences cracking the plexiglas when
the drill breaks through, I convinced the boss to stop by a glass shop
on the way to the job and ask them how to prevent problems.

S000000000 simple! When I asked the guy, and used the word "drill", he
said no no no. Juat take the size drill you need, heat the SHANK end
with a propane torch and push that end through. As the drill melts
its way through, it leaves a little hump of melted and resolidified
material at the edge of the hole. Just take a razor blade and carve it
off.

Pracitce one or two holes first, to get the feel of the drill bit
wanting to slide as it makes the puddle.

---Works GREAT!!! ---Every time!!!

Pete Stanaitis
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I don't know how this would work for holes as big as yours or in the
thickness of the material you're using. For holes in the 1/8" realm,
in material about 1/8" thick, just run the drill fast and backwards.
The friction creates heat and the drill pokes right through in the time
you'd expect it to take to cut through if you were using the drill
properly.

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Rob Skinner
La Habra, CA
www.rustyiron.com