On Apr 13, 3:11*pm, "Orson Cart" wrote:
I scavenged some slabs of perspex (25 mm thick) from a shop that
went out of business. One had a groove cut in it. I guess that
this was made with a plunge router. Has anybody tried this?
I once cut 6 mm thick perspex with a jigsaw, using the finest
blade I could find, but it still made a rough edge.

Donkey's years ago when I made some perspex stuff in the workshop, I
was shown to mill it at a low-ish feed rate, and use parafin as a
lubricant. At the speed routers run, I don't know if that tip is any
use though.

On Apr 13, 3:11*pm, "Orson Cart" wrote:

One had a groove cut in it. I guess that
this was made with a plunge router. Has anybody tried this?

Yes, it's not too bad. The trick is to make sure you're cutting it.
The moment you stop cutting it, you get welding problems. Once you've
welded crud to the tool edge, it won't cut again and it all goes very
bad very quuckly. So use sharp tools, a light cut and a fairly
agressive feedrate so that it's always cutting fresh. Don't let it sit
still and rub.

Plunge cutting is hard. You might find it easier to drill a pilot.

I scavenged some slabs of perspex (25 mm thick) from a shop that
went out of business. One had a groove cut in it. I guess that
this was made with a plunge router. Has anybody tried this?
I once cut 6 mm thick perspex with a jigsaw, using the finest
blade I could find, but it still made a rough edge.

On 13 Apr 2011 15:11:53 +0100, "Orson Cart"
wrote:


I scavenged some slabs of perspex (25 mm thick) from a shop that
went out of business. One had a groove cut in it. I guess that
this was made with a plunge router. Has anybody tried this?
I once cut 6 mm thick perspex with a jigsaw, using the finest
blade I could find, but it still made a rough edge.

Bosch do a jigsaw blade for plastics that cuts perspex as good as the
edges of commercially bought sheets. A few minutes work with a fine
file and a quick pass with a blowtorch and they are perfect.


--

On Wed, 13 Apr 2011 15:29:29 +0100, The Other Mike wrote:
Bosch do a jigsaw blade for plastics that cuts perspex as good as the
edges of commercially bought sheets. A few minutes work with a fine
file and a quick pass with a blowtorch and they are perfect.

Ta - I'll have to look out for that. Last time I did some a few months
ago on 1/8" sheets I used a metal-cutting blade and a light oil as a
lubricant (which was vital to avoid the welding problems that Andy
mentioned). Worked very well (so long as the sheets are well-supported
and not allowed to flex) but took a long time.

cheers

Jules

On Apr 13, 2:23*pm, " wrote:
..

Donkey's years ago when I made some perspex stuff in the workshop, I
was shown to mill it at a low-ish feed rate, and use parafin as a
lubricant. At the speed routers run, I don't know if that tip is any
use though.
A down-cut router cutter helps to avoid break-out but you must keep
the feed up to spread the heat build-up.

On Apr 13, 4:01*pm, Jules Richardson
wrote:

I used a metal-cutting blade and a light oil as a
lubricant (which was vital to avoid the welding problems that Andy
mentioned).

For jigsawing it, use a good jigsaw that's vibration free and the
right amount of pendulum action. This avoids the rubbing on the return
stroke that causes most of the heating problems.

On 13 Apr 2011 15:11:53 +0100, "Orson Cart"
wrote:


I scavenged some slabs of perspex (25 mm thick) from a shop that
went out of business. One had a groove cut in it. I guess that
this was made with a plunge router. Has anybody tried this?
I once cut 6 mm thick perspex with a jigsaw, using the finest
blade I could find, but it still made a rough edge.

We used to cut out the perspex scratchplates for Hayman guitars and
basses in-house on a router table (spindle-cutter?). The standard
single-flute cutter tended to burn the perspex through friction but a
multi-blade cutter worked well. I think the optimum was a three-flute
cutter but I don't remember too well as it was another bloke who did
that job! And it was an awfully long time ago.

Nick