My bet the chassis Punches are knockout punches for Conduit and pipe.

IIRC, the size is the pipe size - the I.D. So if you buy some, check
it
with a ruler. The quality is still tough steel - Greenlee very likely.

I bought a set once - and had to unload it - many years ago now.

Martin
--
Martin Eastburn, Barbara Eastburn
@ home at Lion's Lair with our computer
NRA LOH, NRA Life
NRA Second Amendment Task Force Charter Founder