I'd consider it in two parts, too. One part would be the ½"×½" square with four holes; two horizontally for the threaded rods, and two vertically for fastening to the ftop part.
The top part would be e.g. ½"×⅛" flat bar, with one edge milled to the 60° angle (30° off vertical) needed. Two short countersunk bolts would fasten it to the first part.
I live in a city apartment also, and don't have any power tools at all right now, but I do have enough aluminium to do a few pairs if I wanted to. I happen to have 12mm×12mm anodized aluminium square tubing (Alfer brand, from a hobby store) with 1mm wall thickness, and 2mm flat bar (actually 20mm×20mm L profile or something).
I should even have a suitable 3mm tap and 5mm long 3mm countersunk machine screws, and a couple of 20cm pieces of 4mm or 5mm threaded rod with matching nuts.
Aluminium is soft enough to file by hand to the desired angle, and even a hand whisk drill is enough to drill the needed holes with a good sharp bit; no problem. Instead of a file, I'd actually use wet or dry sand paper at 120, 240, and 400 grit, on top of a mirror, with WD-40 as the lubricant, as that's easier and faster than hand filing. Even the angle is easier to control. (I do have some wood chisels I use elsewhere, that I keep sharp using that same method. I even have all my fingers left, with just a couple of dozen old battle scars here and there; nothing bigger than three or four stitches, though.)
For the countersink, a larger drill bit will do fine.