Picked up two of these Turtlebacks this week. When rotating the handle on one of them there was a little binding, like the screw was tweaked just a bit. Took it apart and sure enough, sighting down the length there's a bit of a bend in the screw.
Use an arbor press to very carefully

take the bend out using blocks of wood to protect the threads.
I put the screw back in and it spins like a champ which was a relief. I'll take it apart again, this time for a thorough cleaning, then put it back into service.
