[Jeff in Pa]

One of the guys on a vintage forum ended up with this tool for cheap and posted a what is it? question and also asked if anyone needed it.

I knew exactly what it was and asked what he wanted for it. $20 plus shipping made me the happy owner of a crank pin turner.

The old engine have babbitt bearings and although they aren't real fussy as far as size, they do have to be round. When the crank throw wears out of round, the tool with the correct width cutter is placed on the crank throw and turned around to make the throw round again.