Re: [bolger] Re: polycarb tip
That's really amazing.
Too often when I've tried to use a regular twist drill on
Plexiglass/Lucite/Perspex/whatever, it's dug in and either split the piece
or lifted a large, nasty spall. Turning the drill slowly didn't help, the
cutting edge still dug in.
One of our machinists in Daytona Beach showed me how he had used a small
slip (hand held sharpening stone) to dull the edges of his drills. The
actual cutting edge was a ninety degree angle rather than the wedge that
results from normal sharpening. He used these on steel and plastic to get a
true hole, and yes, the feed pressure was higher. Perhaps your drills have
been treated this way?
The other worry with normal saws and drills are the microscopic cracks left
by their splitting action. Perhaps the environment for signs is more benign
than that for aircraft canopies.
Roger
derbyrm@...
http://derbyrm.mystarband.net/default.htm
Too often when I've tried to use a regular twist drill on
Plexiglass/Lucite/Perspex/whatever, it's dug in and either split the piece
or lifted a large, nasty spall. Turning the drill slowly didn't help, the
cutting edge still dug in.
One of our machinists in Daytona Beach showed me how he had used a small
slip (hand held sharpening stone) to dull the edges of his drills. The
actual cutting edge was a ninety degree angle rather than the wedge that
results from normal sharpening. He used these on steel and plastic to get a
true hole, and yes, the feed pressure was higher. Perhaps your drills have
been treated this way?
The other worry with normal saws and drills are the microscopic cracks left
by their splitting action. Perhaps the environment for signs is more benign
than that for aircraft canopies.
Roger
derbyrm@...
http://derbyrm.mystarband.net/default.htm
----- Original Message -----
From: "juan negron" <juan.negron@...>
I´m a sign maker in Spain, and go through quite a few pieces of
acrylic ( Plexiglas, perspex, etc are all brand names for acrylic
glass, polymethilmethaacrylate). It comes in many specialty
varieties, but the two major are cast and extruded. If you can get
the cast variety, slightly more expensive, but much more stable, and
much more machinable, do so.
Drill with a regular steel bit, low speed and low pressure. Don´t
rush. use a drill stand if available. You can cut it with a jig saw,
again low speed, and using a blade that is recommended for acrylic or
plastics. In a pinch , a metal blade will do.
Hope this helps.
Juan.
Hello,
I´m a sign maker in Spain, and go through quite a few pieces of
acrylic ( Plexiglas, perspex, etc are all brand names for acrylic
glass, polymethilmethaacrylate). It comes in many specialty
varieties, but the two major are cast and extruded. If you can get
the cast variety, slightly more expensive, but much more stable, and
much more machinable, do so.
Drill with a regular steel bit, low speed and low pressure. Don´t
rush. use a drill stand if available. You can cut it with a jig saw,
again low speed, and using a blade that is recommended for acrylic or
plastics. In a pinch , a metal blade will do.
Hope this helps.
Juan.
I´m a sign maker in Spain, and go through quite a few pieces of
acrylic ( Plexiglas, perspex, etc are all brand names for acrylic
glass, polymethilmethaacrylate). It comes in many specialty
varieties, but the two major are cast and extruded. If you can get
the cast variety, slightly more expensive, but much more stable, and
much more machinable, do so.
Drill with a regular steel bit, low speed and low pressure. Don´t
rush. use a drill stand if available. You can cut it with a jig saw,
again low speed, and using a blade that is recommended for acrylic or
plastics. In a pinch , a metal blade will do.
Hope this helps.
Juan.
As I recall, you need to use a slow tool speed with polycarbonate, as it
melts and grabs. Unless you like buying and changing bandsaw blades.
melts and grabs. Unless you like buying and changing bandsaw blades.
I think Plexi needs to be drilled with a special drill, not just low
speed. If I remember correctly the point is ground almost flat, a
standard drill pulls itself into the plexi, causing the dreaded
cracking. Of course a drill press is a good idea, as a squared off
drill probably wanders all over the place.
Talk to an auto glass company about cutting. The local guy I use here
has no trouble cutting odd shapes in plexi, windows for truck caps,
houseboats, stroefronts, etc., in almost any shape. I haven't been in
his shop when he was doing it. But I bet such a visit would be an eye
opener.
Bruce Hector
speed. If I remember correctly the point is ground almost flat, a
standard drill pulls itself into the plexi, causing the dreaded
cracking. Of course a drill press is a good idea, as a squared off
drill probably wanders all over the place.
Talk to an auto glass company about cutting. The local guy I use here
has no trouble cutting odd shapes in plexi, windows for truck caps,
houseboats, stroefronts, etc., in almost any shape. I haven't been in
his shop when he was doing it. But I bet such a visit would be an eye
opener.
Bruce Hector