Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!uunet!zephyr.ens.tek.com!tekig5!brianr
From: brianr@tekig5.PEN.TEK.COM (Brian Rhodefer)
Newsgroups: sci.electronics
Subject: Machining Plexiglas
Message-ID: <5386@tekig5.PEN.TEK.COM>
Date: 15 Jan 90 19:31:40 GMT
Distribution: na
Organization: Tektronix Inc., Beaverton, Or.
Lines: 21

While I was going to college, I had a summer job with a firm
that specialized in products called "lightplates", which were
.2" thick (or so) Plexiglas panels that provided illuminated
legending for aircraft cockpit controls.  All the cutting tools
that we used, whether carbide-tipped or not, were custom-ground
for use with Plex.  The crucial feature, I was told, is that most
"stock" mills, drills, and blades are sold for use on metals, and
have a shallow "rake angle" - the angle that the cutter's leading
edge makes with the work surface.  Plex tends to burn and "grab"
badly with these kinds of cutters, and works best with rake angles
near 90 degrees.

To see the effect, try smoothing off the cut edge of a scrap of
Plexiglas with a pocketknife.  You'll get the best results when
you use the knife as a scraper, perhaps even with a negative rake angle.


If you do a lot of work with Plexiglas, you might try asking for
Plexiglas cutting tools next time you buy drill bits or sawblades.

Brian Rhodefer