Perhaps a bit off topic, but here goes...
In a recent post,
looking for a 40M QRP SSB kit, Fred (K3TXW) explained, "...I have problems making a rectangular hole in a piece of aluminum of exactly the right size, with the edges exactly parallel to the edges of the case. I inevitably make the opening too big or slightly wavy. The result screams "homebrew carelessness" though I'm not careless. Maybe there is a rectangular punch or something to do this right, but I don't have such a tool; I use a set of files."
In addition to files for work on front panel fabrication, I recommend an electronics shop include:
1.? A drill press with a chuck that will accept 0.50-in.-diameter bits.? Harbor Freight sells a couple of bench-top units for under $100.? Put a magnet on the base as a place to keep the chuck wrench.? (It's usually best to clamp work to the drill press table.)? Once you have a drill press you'll find many other jobs for it.
2.? A good set of
sharp drill bits.? Bits with a titanium nitride coating remain sharp for a long time.
3.? A step drill bit.? I use an
Irwin Tools Unibit 3/16-Inch to 7/8-Inch Step-Drill Bit with a 3/8-Inch shank.? Great tool when you need to make larger holes for controls or to start a rectangular cutout.
4.? An Adel-brand metal nibbler.? They show up on Ebay.? Or buy a new one at .? I've used one since I was a teenager and couldn't work on chassis or panels without it.
Lay out your hole with masking tape around the outside.? To make a rectangular hole (see attached image) I use a step bit and smaller bits to make round holes that remove a lot of metal.? Just don't get too close to the rectangle's edges.? Next I use the nibbler to remove remaining metal close to, but not at, the rectangle edges.? Finally I clamp the panel or chassis in a bench vise so an edge of the hole aligns with the top of the vise jaws.? File away any remaining metal until the edge is parallel with the vise jaws.
--
Jon Titus, KZ1G
Herriman, UT USA
