So there's this thing I've wanted to make for a while that got back-burnered. I was planning to make it out of right-angle steel stock from a hardware store, and asking my brother or a friend to do the welding. Seeing almost the thing I wanted in a catalog reminded me of this project, and I thought of a way to do the corners that I don't think I'd considered earlier.
Does it make sense to cut a notch in one side of the stock, then bend the piece over a brake until the edges of the notch meet, and weld the cut edges together, as shown in the top set of figures below?
The other methods that I'd thought of were to make a miter cut and weld the edges, or (as suggested by my brother who has actually done some welding) to make straight cut, overlap the edges, and include enough slop in the other aspects of the design to account for the pieces on either side of the corner being offset by the thickness of the stock.
([Whoops -- there's an error in the last drawing -- an extra welded edge drawn where none would be. I'll put up a corrected drawing later.] The green marks in the diagram represent welds (assuming welding works the way I imagine).)
Most of the corners I want to make will be right angles. Two will be obtuse (probably either 135° or 150°).
The thing I want to make is a custom portable desktop rack for musical electronics, with a vertical section for effects and a sloped upper portion for a mixer, similar to the configuration in one of those pop-up mixer+other-stuff rack/case combos, but open-frame instead of built into a case, and hopefully much cheaper. I saw a similar open rack with only a sloped face in a catalog for a lot less than I expected, but it's too steep for what I want -- it'd be fine for just a bunch of racked guitar effects on stage, but not so comfortable to use for a mixer.