i'd be lying if i told all of you i knew a thimble full of anything, but here we go..
in looking in a old machine book a while back, i saw a metal tubing forming that was identical in design, albeit a little larger.
it was used in conjunction with a pointless live center in the tailstock that extended into the pipe end to produce a flange in the end of a tapered sheetmetal duct.
i don't know if this is the same tool or not. sure looked similar though:thinking: