Newsgroups: rec.crafts.metalworking
Subject: Re: Cutting Plexiglass on Table Saw?
From: dwilkins@northernnet.com (Don Wilkins)
Date: Tue, 26 Dec 1995 14:01:14 GMT

On Mon, 25 Dec 95 22:23:17 PDT, tabco@acy.digex.net wrote:

>>    Having just has a pretty unpleasant experience cutting
>>    plexiglass on my table saw, I am wondering if anyone
>>   has suggestions about how to  make it better in the future?
>> 	 
>Dave......Just scribe, and snap.  They make special tools for 
>this too........Fletcher-Terry  (sp) made the one I have.  
>Works for lexan too.


Yes this is better than cutting on a table saw but it is a little bit
more than scribe and snap. You should use the special cutter and
contrary to glass cutting go over the line enough times so that you
have cut a fairly deep groove. The best way is to use equipment such
as the Fletcher but you can purchase special hand held knives for this
purpose. If you don't have a Fletcher, clamp a guide to the plexi so
that you can go over the line several times.

  _               _   _                  Für d' Flöh gibts a Pulver 
 (_|   |   |_/o  | | | |  o              für d' Schuach gibts a Wix, 
   |   |   |     | | | |      _  _    ,   für'n Durst gibts a Wasser
   |   |   |  |  |/  |/_) |  / |/ |  / \_  bloss fuer d' Dummheit gibts nix.
    \_/ \_/   |_/|__/| \_/|_/  |  |_/ \/ 

Newsgroups: rec.crafts.metalworking
Subject: Re: Cutting Plexiglass on Table Saw?
From: shoppa@altair.krl.caltech.edu (Tim Shoppa)
Date: 26 Dec 1995 16:38:52 GMT

In article <NEWTNews.819959093.26469.tabco@acc11022.slip.digex.net.digex.net>,
 <tabco@acy.digex.net> wrote:

>>    Having just has a pretty unpleasant experience cutting
>>    plexiglass on my table saw, I am wondering if anyone
>>   has suggestions about how to  make it better in the future?
>
>Dave......Just scribe, and snap.  They make special tools for 
>this too........Fletcher-Terry  (sp) made the one I have.  
>Works for lexan too.

Scribing and snapping is fine for straight cuts and broad curves,
but intricate acrylic cutting (especially of thick pieces, as
are likely to be found in model making) requires a good saw blade.
Luckily, specialized blades for cutting acrylic are available from
plastic supply houses.  They also have drill bits that actually
make holes in acrylic instead of a gooey mess, and remarkably
good cutters for milling, and taps and dies for cutting threads
in acrylic.  Sure, you can do all of these operations with conventional
metalworking tools and get good results if you are slow and
careful, but the tools intended for acrylic are so much faster
and easier to work with.  I'm going by my local plastic
supplier today; I'll see if they have any brochures or catalogs
to give away.

Newsgroups: rec.crafts.metalworking
Subject: Re: Cutting Plexiglass on Table Saw?
From: shoppa@altair.krl.caltech.edu (Tim Shoppa)
Date: 27 Dec 1995 01:08:35 GMT

In article <4bp8es$gvm@gap.cco.caltech.edu>,
Tim Shoppa <shoppa@altair.krl.caltech.edu> wrote:

>  I'm going by my local plastic
>supplier today; I'll see if they have any brochures or catalogs
>to give away.

I went by Paragon Plastics in South El Monte today (it's literally
just a couple of blocks from Industrial Pipe and Steel) for a replacement
acrylic front panel for one of my 9-track tape drives (a Digi-Data
swing-arm transport) and while I was there I saw they had a whole
wall full of "Tech Briefs" on plastic fabrication.  In particular,
the following information is from the Acrylite FF Tech Brief #2,
"Cutting with Circular Saws":

1.  Use a carbide-tipped blade.
2.  For general purpose cutting, use a 10 inch, 80 tooth blade.
3.  The blade should have a triple-chip design - every other
    tooth has a beveled edge for clearing away chips.
4.  The saw blade teeth should have a clearance angle of 10 to 15 degree
5.  The blade should protrude about 1/8 to 1/2 inch above the
    work piece to yield a smooth cut.
6.  A faster feed rate actually minimizes frictional heat between
    the work and the saw blade.  50 ft/min is recommended as a
    starting point.
7.  A mist cooling system helps to minimize heating as well.

For the problem that I typically had when I was doing table-saw cutting
of acrylic, melting gooey plastic, there are two recommendations:
Increase blade penetration into work, and Increase feed rate.
These reommendations are in a way very counter-intuitive to me.
While cutting steel, for example, if the work begins overheating,
I will slow down the feed rate.  According to the brochure, though,
if acrylic overheats while you're cutting it, it is best to increase
the feed rate!