It is from my deceased Uncle's tool box. He mostly had inexpensive automotive tools, but also had other stuff that he must have used or modified to use as tools.
It is chromed steel, or at least is shiny like a brushed chrome. On one end is stamped "HARDENED STEEL", and on the other end "TAIWAN-LAP" or "TAIWAN-LAF". The overall size is 7/16" square by 7-1/2" long; one end is tapered to a square, the other end is a tapered hexagon. The square end tapers for 1-3/4" from 7/16" (at main section) to 7/32"; the hexagon end 1-1/4" is tapered from 3/8" (at main section) to 7/32".
I initially thought that it might be a punch (it obviously has been used as one), but why would you want to damage one end (or both ends) by mushrooming? I also thought it might be a wrench-like tool, perhaps a tool made specifically for an individual item (think an assembly tool like Ikea provides), but would it make sense to taper such a tool? It might be part of a set, perhaps like a die and stamp, or might be part of a tool (perhaps there should be a handle at one end). I'm thinking that perhaps it is part of some sort of speciality tool.
So, what is it? What does it go to? What is it for?
