Slightly OT: tips for fabricating with plexiglass?

From: Pete Turnbull <>
Date: Sun Jan 16 05:45:51 2005

On Jan 15 2005, 18:51, Computer Collector Newsletter wrote:

> I've heard some horror stories about whole (expensive!) sheets of
> simply breaking in half when incorrectly drilled through. The guy at
> plastic supply company tried selling me a special drill bit, but I'm
> about that. Does anyone has hands-on experience and tips (vs. just
> speculation) about working with this stuff? This computer will be on
> as some public events, so the final appearance is very important.

The biggest problem is likely to be as the drill bit breaks through.
 If you look at the end of a twist drill you'll see that the centre
doesn't cut in the same way as the edges, and it's the force of the
centre distorting the plastic as it breaks through that causes cracks.
 The other problem is if you don't have enough control of the drill,
and the bit "snatches".


    use a really sharp bit

    drill a small pilot hole first, and maybe enlarge that to some
    intermediate size so the pilot hole is a little larger than the
    point of the final drill

    put the plexiglass on a smooth block of wood or spare plexiglass,
    hold it down *firmly*, and drill through into the wood (make sure
    there's no swarf from earlier holes trapped between the plexiglass
    and the sacrificial material)

    run the drill slowly enough to avoid generating heat, but keep
    just enough pressure on it to ensure it keeps cutting, and
    doesn't rub

    use a drill press, not a hand-held drill

    practice on a piece of scrap first

I drill lots of plastics, some very brittle, this way.

Pete						Peter Turnbull
						Network Manager
						University of York
Received on Sun Jan 16 2005 - 05:45:51 GMT

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