Adapters for 1/2" bolt (fine/coarse thread) to 6 mm flexible coupler

I am using 12V crab pot puller motors with hollow shafts for my 6DOF rig. I put 1/2" bolts through the hollow shafts to attach my levers. I wasn't happy with my original approach of drilling a hole in the end of each bolt and gluing in a short piece of 1/4" rod to attach to the flexible coupler for my position sensor. It was difficult to get the hole centered in the bolt, and that made the connection to the flexible coupler pretty eccentric. So I made these to get better concentric motion. I know it's a pretty specific application, but I figured if it would save anyone else a little time and trouble, I'd post them.

On the advice of another user here, I'll be switching to fine thread (1/2"-20) bolts to connect my levers to my motors, so here's a link to a fine thread version of the adapter. Hope it helps someone.