Bob at the church thrift shop explained that this interesting-looking tool was used in working with cement to tighten or adjust the wires. He did not know what it was called.
Good ol' Google took "tool" and "wire" and "twist" and came up with many images and that led to what it is called and how it works here.
Having knit with wire and considering it 'fibre', I got to wondering how this tool would work with wool and cord and clothesline rope and ripped cloth etc.
As soon as I got it home I took some cotton string, tied it into a circle, hooked it on a doorknob. stretched it out and hooked the end to this tool and gave it a twirl. Wow! It twisted easily and efficiently. And I had an almost instant (compared to hand and finger twisting) four-ply cord.
It is fun to use. You hold the wooden handle and make circular wrist motions which twirls the hook.
One dollar. People keep suggesting I mention what I paid for these finds.