Mystery tools - what the heck are these things

Ok...I will play at least a bit. The first item looks like a blade for scraping metal (cast iron) surfaces flat. Used fairly often for dealing with wear on lathe/surface grinder ways. I would guess that the "height gauge" is actually a press for locating a press-fit item in another piece. The pins on the support block would locate the work piece, and, the press is set to push another part into it to a precise point. The holes in the top might well be for locating pins on the top of the piece being pressed in place. Not a clue about what the diode is used for, but, that is not unusual. There are a LOT of special purpose electronic bits out there. Regards Dave Mundt