Hah ACRYLIC, this is a wonderfull thing to play with in the lathe, SHARP toolsteel is the way to go to cut this stuff. You can play with it at ANY speed you want to try, the only thing you have to watch out for is, if you just so happen to allow the tooltip to dwell a bit longer than normal, it will heat up and then start to melt it, instead of cutting it.
The trick to learn, is to watch the swarf coming of the tool, so long as it's coming of cleanly and flying away from the tool-tip, no worries, keep cutting. The moment that the swarf slows down, in other words it's not flying out thru the air, then just get your tool out of the way, no melting it then.
A little bit of practice will soon show you what the swarf flying of the tip should look like. I've cut this stuff thousands of time on a Unimat 3 - FLAT OUT, that's 4000 RPM, no melting it at all, just a bloody great big mess of acrylic swarf all over the place, by the way, this stuff is full of static electricity and it seems to want to stick to anything and everything that it can. Shitty stuff to clean up, but that's about it's worst fault.
It does not like being cut at too slow a speed, as it is brittle, you gotta keep the revs up, along with the feed rate up as well.
This stuff can be turned into glass real easy, just turn to whatever shape you want, then get some wet and dry, start at about 600 grit and rub the bit watching for heat build-up in the wet & dry, the moment you can feel the heat in your finger tips, quit and allow to cool. You can use the wet & dry either wet or dry, the dry clogs up real quick and the heat build up fast as well, or use a drop or two of water on it, you'll soon notice when it's starting to get hot, think of finger tips in boiling water about now.
The revs here are dropped down to 1500 RPM for the polishing, as to many revs equals too much heat, follow me drift, go down to 1200 grit, then 1800 grit, about now it's looking a bit cloudy clear.
For the absolute best, go get some of this stuff.
http://www.winterbrookfarmantiques.com/product_info.php?products_id=1102?
You can buy it anywhere, use a soft cotton bit of cloth, apply a small bit to the rag and start to polish it, watch for the heat build-up again, keep moving it around, don't dwell on the one spot too long and pretty soon you got a bit of glass looking at you.
I've used this stuff for making bits for models for about 20 yrs, DO NOT BUY IT, it will break the bank instantly, go find a sign-maker or someplace that uses this stuff, now you all heard of DUMPSTER DIVING, good for the fitness fanatics as well as your back pocket, plenty of it and it's freely available.
regards greenie
have put a stop to that method.
