On Jan 15 2005, 18:51, Computer Collector Newsletter wrote:
> I've heard some horror stories about whole (expensive!) sheets of
plexiglass
> simply breaking in half when incorrectly drilled through. The guy at
the
> plastic supply company tried selling me a special drill bit, but I'm
hesitant
> about that. Does anyone has hands-on experience and tips (vs. just
> speculation) about working with this stuff? This computer will be on
display
> 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".
Tips:
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