OK, it's not WWing, but related. Hoping some of your craft-ivores have helpful ideas.
I have an ABS plastic box - 5x4x2in with a removable 5x4 cover.
I need to cut 2 rectangular windows in that cover, approximately
1x3 in. For cosmetic reasons, they need to be well aligned above each other and parallel to the 5" edge of the 5x4 cover, and centered theron.Can anyone suggest a good cutting method of achieving this, short of buying a CNC mill or the equivalent?
TIA,
Three approaches that I can think off off the top of my head.
Probably the best for someone who is used to woodworking tools would be a Jeweler's Saw. It's kind of like a coping saw but the blades have incredibly fine teeth and will cut just about any common material very precisely and very smoothly. Need to drill a starter hole (it can be tiny) and work very carefully and patiently to get a straight line. Might want to cut close to your mark and finish up with a flat file (the ultra fine tooth kind you get in a set of "swiss files").
Hot knife is the classic way ("hot knife" in this context is an exacto blade in a soldering iron--you can rig your own or buy one commercially for not much money). Plan on a little clean-up--they tend to make a little bit of a lip around the cut edge.
For either of these, you might want to get a piece of ABS scrap to practise on.
A nibbler will also work. For a one-off in ABS one of the little hand-held jobs that Amazon sells for under 20 bucks should be fine. sneak up on the cut line and plan on filing the last bit to be sure it's smooth. Neat tool--punches out little square chunks, so it makes square corners--usually a sheet-metal workers tool. Needs a starter hole.
Router, template, and flush trim bit.
First, you need to lay the cut areas out accurately, no matter how the cuts are accomplished.
One way is to make a paper drawing that can be temporarily stuck to the ABS sheet to be cut, and cut on the lines through the paper.
Another way is to use a metalworking surface guage and a flat workbench surface to lay the cut lines out directly on the ABS sheet.
This shows the general approach:
For woodworking, this level of precision is not needed, and one can use the idea if not the expensive full-precision tools. Used surface gauges are available in used tool stores for small dollars.
Then, use a jewlers saw to cut on the lines, as others have suggested, but with a twist: Use plain water to lubricate and cool the cut. Use on oil, as this will later cause the ABS to crack or craze.
Joe Gwinn
How would your Origin handle this job?
Just so we're all on the same page, When I say "jeweler's saw" this is what I have in mind:
Is that the same thing you refer to? The reason I ask is that I've never found it necessary to use a lubricant or coolant with one when cutting plastic, so it occurs to me that you might be thinking of something different.
Agreed - maybe one of those inlay bushing and bit kits like this:
I think that should say "use no oil". It makes more sense that way.
I was cutting some plastic a couple of months ago, pretty sure it was polycarbonate not ABS, and I sure had problems with over heating. If I cut too fast the plastic would melt but then it would seize up before the chip was clear of the tool. I had to clean a lot of small rock hard plastic bits out of the teeth of the saw.
The initial plan to use powered jigsaw had to be scrapped and my first cuts were pretty awkward until I got slow enough.
Drilling holes through it also involved some care.
Elijah
------ is prone to bad typos in posts
Very well, just like this,
If you have to explain twice, it's probably overly complicated. ;~)
Yes, that's a jewler's saw. Although there are better choices than Dremel.
Although I called the water a lubricant (common terminology in metalworking), as others have said, its real purpose here is to cool the plastic and prevent it turning gummy and melting into a mess, and clogging the saw teeth up.
Plastics vary, but hard thermoplastics (like polystyrene, polycarbonate, and polystyrene) can often be induced to melt while cutting.
But use no oil at all.
Joe Gwinn
That hole seems to be roughly cat-sized. ;-)
Would the Origin work as well for a 1" x 3" hole or is it too much tool for something that small?
Shaper Origin?
On a related note, any idea how to cut HDPE? I have some 2-1/2" strips out of an 1/8" sheet.
The cat agreed the instant I placed the unit on the customer's floor.
It will cut as small as a bit diameter, like a drill press if necessary. So with a 1/8" collet you could accurately drill a 1/16" hole.
For small stuff the Shaper Workstation comes in handy.
HDPE is easily cut on a band saw running slow (as for steel), but don't expect great precision. Respect the rule about two teeth min in the material. I use a metal-cutting blade.
Hmm. I have one of those bandsaws with a gearbox, and so can be used for cutting metal. Not all bandsaws can do this. I'd bet that one can cut HDPE with a wood blade running at wood speeds, but have not tried this. I have done this on a table saw, though.
One can dress the sawn edges with a very sharp low-angle block plane intended for woodworking.
Joe Gwinn
Many thanks to all who answered here. Upon further analysis, I am going to give this a shot:
Many thanks to all who answered here. Upon further analysis, I am going to give this a shot with a drill press and end mill bits:
The only question I have is ... what speed should the press be set up for?
You will need to cool the cutter and workpiece with water. If you run too fast, the workpiece will melt no matter what. So, experiment.
Also, make sure that the workpiece is clamped firmly, or it will be caught and mangled,
And, be afraid of the rotating mill - it can catch your clothes and cut you up a bit.
Joe Gwinn
Two teeth is pretty tough in a 1/8" sheet.
Maybe I'll try a small cut. I don't know how much extra I have. The sheet was relatively expensive so didn't buy more than I needed.
I'm not too much worried about a perfect edge. I'm using it as a spacer so it won't be seen.
Thanks for the ideas. Evidently I have some experimenting to do.
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