I came across this illustration of a saw for cutting perfect 90 degree angles by hand (for example, when cutting out the pins in a dovetail). It’s apparently something that used to be common in the German and Austro-Hungarian woodworking traditions, but is no longer a standard item anymore. I’ve got 0 metalworking experience, does anyone have any ideas how one would go about making one of these? Maybe it would be possible to start with a big coping saw blade and modify it somehow?
The idea is that you insert the toothless part of it into your vertical kerf, and then you push forward and the teeth get pushed in at 90 degrees and cut across, and then you use the back third of the saw to finish the cut.
Maybe someone else finds this fascinating enough to help me make one? Maybe trade for some dovetailed boxes that I would then make with the saw?