I picked up a “almost” complete lot of machining tooling for a set of lathes. One item that was missing was a clamp for the tapping head. I reasoned out a quick idea of how it worked and what was missing and did a quick sketch in Fusion and produced a quick part without the outer filet. I also drilled the corners so I wouldn’t need to broach the corners. Saying still holds, if you can’t find it, make it.