Before we start drilling, let’s take a moment to review some basic drilling
safety practices, which apply whether you’re using a hand drill or a drill
press.
1. Drilling aluminum produces small, sharp pieces of metal
(“curliqueues” or “chips” as machinists call them). Safety glasses or a
face shield are essential, and work gloves help protect your
fingertips.
2. The bit can bind in the material, and cause the box to spin on the end
of the bit. This is dangerous, as it can damage the box, the bit, and
your fingers. Secure the box with a vise or clamps before drilling!
3. A little lubricant can help the bit cut more smoothly, and prevents
dulling. There are specialty machinist’s bit lubricants, but if you don’t
have them handy, a few drops of light household oil will help.
If you’re using regular bits, start with smaller ones, then work up to larger
ones. We began with a 1/8" bit to make pilot holes on each of the center
punch marks, then worked progressively up to larger bits. The five holes for
the rotary switches should be drilled to 3/8".
The two banana connectors fit in 5/16" holes. Lacking a 5/16" bit, we drilled
them to ¼", then filed the holes until the connectors fit.
If you’re not enthusiastic about all of those bit changes, consider using a
stepped drill bit, such as the Irwin Unibit.
Once the holes are drilled, consider using a countersink to deburr and bevel
the holes, to remove any sharp edges left by the drilling.
Labeling
In the decade box GitHub repository, there is an SVG file of the panel
legend. If you have access to a laser engraver, you can etch it into the
enclosure.
If you aren’t lucky enough to have access to a laser cutter, you can simply
print it on paper, trim it to fit, and stick it on with adhesive tape.
Electrical Assembly
Bill Of Materials
Before we start soldering, let’s verify that all of the parts are present in the
kit.
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