Metalworking Advice

I'm thinking ahead to an enclosure for an Arduino project I'm working on. Although I have not yet chosen a specific box, it will almost certainly be aluminum (somewhere around .050" thickness). There will be rectangular components (e.g., an LCD panel and a numeric keypad) mounted on the front panel of the enclosure, so I will need to cut rectangular holes. I do not have access to a machine shop (which is just as well, since I wouldn't know how to use it if I did).

Three possibilities come to mind for cutting the holes:

  1. Remove most of the material with a Dremel tool using a fiberglass-reinforced cutoff wheel, then clean up with a file.

  2. Drill holes (probably in the corners), then remove material with a hand nibbler tool, then clean up with a file. (I do not own a nibbler, but I'd be willing to buy one if that's the best tool for this job.)

  3. Drill one or more holes, then remove material with a jeweler's saw (not sure what blade), then clean up with a file. (This may not be feasible; I haven't yet done the layout, so the saw may or may not have a deep enough throat to cut all of the holes.)

Any suggestions as to which of these alternatives (or any other ideas) would be best would be appreciated. Thanks.

Rob Rothman

I would go with a small hole at the corners and a large hole(s) in the waste to get the saw in.

Dremel toothed cutting wheels can be had which cut ally ok but cannot be used freehand.

Carbide wheels will clog with ally.

Nibblers, not a big fan they can deform the edges too much.

Qmax cutters can be used for holes but big rectangular a too expensive and require a press.

Have you thought about getting them laser cut before you bend them ?

Ive done a few front panels in acrylic which are fairly cheap to have done , ofte postage being the largest cost.

Edit Afterthought.

If you are thinking of using diecast boxed, they are an alloy, it may be possible to cut those with a carbode wheel.

I'd suggest a zinc diecast box as they are less prone to distortion, are relatively easy to cut and drill and do not tend to clog drills or jewellers saws as aluminium will. Add to that, they can come ready painted, have nicely rounded off corners and edges and most come with cast in slots to hold circuit boards in place.

I'd concur, diecast boxes are more rigid and cut well - be aware they are more brittle than steel or aluminium, so don't go crazy. However this makes nibbling a lot easier.

If you do go with aluminium try to avoid pure aluminium (1000 alloys) as they clog cutters and leave great big burrs on cutting. High strength aluminium alloys like 6000 series cut much better and are much less soft. In my experience it seems that anodized aluminium products seem to be high strength alloys (perhaps the anodizing just crazes if the base metal is soft). Anodized aluminium is good for front panels as it much more wear/scratch resistant and looks good untreated/unpainted.

Im not sure of the exact alloy but eddystone boces are ally with a zinc plate these days , i assum thats what is being referred to. Zinc diecast is used mostly for connector bodies these days.

I normally do it this way.

  • Make a cad drawing
  • Print the drawing 1:1
  • Glue the drawing onto the panel with aerosol stencil glue
  • Use a optical center punch to get the holes positioned exactly
  • Use a scroll saw for square (and other non-round) holes. This may require some cleanup depending on how good you are with the scroll saw.
  • Remove the residues of the drawing and clean up and deburr the panel

The optical center punch and the scroll saw are some investments but i have used mine for years now and the method i'm describing gives you excellent precision

Laser cutting the panels is an option i go for sometimes

You could rough cut the holes in the box then add a plastic bezel over the hole(s) mark them from the back, then cut the holes out with hand tools. IMO pastic is usually easier to work with and finish. I use this material for the bezels, gravoply. Google gravoply images

See: http://forum.arduino.cc/index.php?topic=219747.0

Another option - if the wall thickness isn't too crazy - would be to use a chassis hole punch. That said, finding square or rectangular punches can be difficult - and when you do, they can be very expensive (whereas round punches are fairly easy to find, and relatively inexpensive).

Here's a Make article that discusses various ways to make square holes in metal - which may help you:

http://admin.makezine.com/extras/15.html