Yet another plexi cutting/drilling thread

[stratjakt]

I know there have been others, but I haven't seen anyone suggest this, or post results, but I read about it on an unrelated forum..

I have a metal CP, and I want to make a plexi overlay, and for my idea to work right, the holes have to be dead on.  I don't have a drill press, I do have one of those "attach your drill to it and make it work like a drill press" things, which works OK for wood projects, but unlikely in this case. 

Anyways, the idea I found, was to use a dremel with the standard rotary cutting tool - the one that's like a sharp drill bit, clamp the plexi to the metal CP, drill pilot holes, and basically slowly use this to follow the curves of the CP holes, cp outline, etc.  Then flame polish or wet sand, or finish the edges however.

It sounds like it would be easy, and work well.. Anyone give anything like this a try?  I find working plexi with regular power tools (jig saw, drill, circ/table saw) to be rather awkward.

[DrewKaree]

Make a template from some hardboard or MDF.  Then take a router with a pattern bit, slap the plexi on top, clamp it, and make yourself a copy.

[Abomination]

The problem with the dremel way is that there is no bearing on the bit.  The way routers work to copy holes and such is that a bit with a bearing is used.  The bearing rides on the original while the cutter removes the material from the new piece.  If you use the dremel it wont stop when it hits the metal piece and unless its aluminum it will probably break the bit which could be very dangerous. 

As for your problems with working with plexiglass...  If you use the correct bits/blades and go at whatever the machines slowest setting is it should be just as easy as wood to work with, hell easier because there isnt any grain to contend with.

[stratjakt]

I can live without a bearing since the CP I'm copying is fairly thick steel, and I'd have to really lean on it to cut into it.

I find a jigsaw awkward because when it goes slow, it gets caught and wants to jump out.  Table saws and skil saws only have one speed.  Scoring and snapping works ok for me most of the time.

Drilling with a hole saw works OK for me too, but it'll tend to wander the slightest little bit no matter how careful I am.  With plenty of projects I wouldnt care, or if it was a new wood CP and I was drilling both at the same time, it'd be OK, but in this case I need the plexi to match up 100% to the CP, with a tolerance of +-.0001% of a micron.

[DrewKaree]

Then routing this with a pattern bit is going to be the best solution to achieve that result.  If you don't have a router, you most likely can rent/borrow one. 


Anything else is a crapshoot.


If you were the kind of person who'd end up with decent results using something else, this would be a mute point, for all intensive porpoises.

[stratjakt]

Using the dremel spiral cutting bit at about half speed worked like a charm.  It wasn't spinning fast enough to bite into the metal of the CP, but fast enough to cut through the plexi like butter.  A little light sanding and it looks great.  Wood panel would be different, but with a steady hand it'd be really doable.  If you set the bit right, only the shaft part would be in contact with the wood, not the actual cutting part, and would act somewhat like a bearing.

For funzies I clamped a straightedge onto the piece and used the cutting foot attachment base dealie, cranked the speed up, and cut a straighter smoother line than I'd ever done before..  The high speed melted through, but made enough of a gap that it didn't fuse back together, the result was not unlike a flame polished edge.  The triangle/cone cutting bit would probably pull off a pretty nice beveled edge, I think I'll try it next.

I'm using my dremel for cutting everything from now on. 

Now if you'll excuse me, my puppy needs to be neutered and I need some more cutting wheels.