succio had some good suggestions.
you could drill a hole in a doll/dall (however you spell that) rod, suspend a rope from it, and attach a plate to the bottom end of the rope, then practice winding and unwinding it. screwdriver motion can't really be achieved many
other ways and it's really effective.
also, pullup bar hangs. you ever
see how
big an experienced mountain climber's forearms are?
wrist curls, reverse wrist curls, waiter walks (hold the plate up with your fingers like a waiter carrying a dish in a restaurant), farmer walks (youtube it), plate pinch, grippers, hammer curls for that bump... there are a million wrist exercises.
wrist strength is something i struggle with too but don't go the easy way out and use
gloves or some bullshit. build the muscle needed to increase your grip. but do it AFTER you get some surgery for that carpal tunnel.