I made a couple mini squares from standard speed squares, to use in wood or metal working shops. I made one from plastic and one from aluminum and both work really well. I found myself reaching for one much more than I expected, so I made another aluminum one to keep on my bench in the barn. I use the cheapest speed squares I could find, in the $2 range. Most of the better brands have more slots for options, and those slots make them unusable for this. I attached pics of the new square with a red line indicating where I'll cut it with a hack saw. Then a pic of it cut. And finally the mini square. I clean up the fresh cut edge with a file, as well as any burrs on the other edges. This last one took me a total of 2 minutes to cut and file. By looking at it, you wouldn't think it makes much difference to have a standard or mini size, but that smaller size can be used easier in tight areas and also fits in a large pocket.
