View Single Post
Old 01-17-2011, 12:34 PM   #2 (permalink)
Rokeby
Gen II Prianista
 
Rokeby's Avatar
 
Join Date: Jul 2009
Location: Ballamer, Merlin
Posts: 453
Thanks: 201
Thanked 146 Times in 89 Posts
Longish post follows.

I am a boat builder/wood worker, but from time to time I get involved with
working sheet plastics, mostly for instrument panels, small windows, etc.
So,I have some limited experience here.

What you've shown is typically called a "wing cutter." I would be reluctant to
use it, especially where a smooth, finish is desired on the cut edge. The
difficulty with the wing cutter is that almost inevitably as the cutter gets to
the bottom of the hole it "breaks through" and then twists/tears/breaks the
hole edge somewhere along the circumference. Damn!

In general, it is recommended that holes in Plexiglas at any rate be made
with a course toothed hole saw in a sturdy drill press. Typically something
like this:

They are available in sizes from ~1/2 inch up to :

(If that saw catches on something and stalls, the operator is risking one
or even two sprained wrists. For uses like this the drill motor should
have two directly opposed handles on the sides of the drill body.)

The hole will be somewhat ragged, showing tooling marks from the drill's
teeth. To get a really smooth, finished look/feel, I have heard that you first
cut a slightly undersized hole with a hole saw, and the re-cut the hole to
desired/final size with a router with a spiral cutter. Something like this,
where the amount of material to be removed, ~1/8 in., 3 mm, is less than
the diameter of the cutter:


You'll need to make custom sized jigs for each hole size to be made
The router doesn't have to that powerful, a laminate cutter or RotoTool
should do fine:

For a more formal discussion of these matters from pro's, here's a good
place to start, See especially the PDF download at the end:
How to Fabricate Plexiglass - cutting plexiglass from ePlastics.com

[EDIT] You may also want to consider a small CNC machine to do this.
Here's one that is designed solely for sheet goods that comes as a kit
for ~$1000 USD. It may not be quite wide enough for what you need :

(I'd kill for one of these!)

Phlatprinter 3 Kit

Best of luck to you.

Last edited by Rokeby; 01-17-2011 at 12:58 PM..
  Reply With Quote