I found this chuck on EBay. When I saw it, I instantly knew what it was. It’s another oddball. And I think some machinists just would prefer to use a 4 jaw. But, I wanted to give it a shot.
It’s a Rohm 3-jaw scroll lathe chuck with adjustable jaws. It’s like an Adjust-Tru.....but it’s. Three jaw. And a little different design since there’s a 1/4” Allen adjustmen screw integral to the jaw. The jaws are reversible.
Rohm 3-jaw self centering 8” lathe chuck- 1800.00