Wrist training device, for example for strenthening wrists for climbing. Ensures the wrist needs to put out a constant torque when doing for example wrist rotations, wrist tilts or hammer curls.

Assembly: Thread a 80-120cm long 5mm or 6mm paracord through the device. Make 2 overhand loop knots at the ends. Add some carabiners. Fasten some weight to the carabiners, I just used the attached PET-bottle adapter and clipped a couple of water bottles as weights. You might want to cut the rope to perfect length after you've tried out the fully assembled device, I ended up just needing 80cm of 5mm cord.

Wrist rotations: Fasten a weight to one end of the cord and let the other end slide into the device. Rotate the write 180 degrees, letting the cord go over the beveled part of the device. This ensure you have a constant resistance on the wrist through the entire motion. See pictures.

Wrist tilts: Fasten both ends of the cord to the load plate and a weight on the center carabiner. Put the cord in the slots in the ends of the device and let it be carried in the runnels. Support your forarm on something and tilt the wrist up, repeat for back and front. This ensure you have a constant resistance on the wrist through the entire motion. See pictures.

Note: take it easy when starting exercising for the first time, don't do too many reps or too much weight or you might hurt something. You should probably build up to more reps and weight gradually.

Sizes: I included 3 different sizes of the device. The photos show the medium device in the hand of a male with average sized hands. If you have small hands you might want to print the small version, if you have huge hands and long fingers go for the large version.

Complete CAD document: https://cad.onshape.com/documents/b2a3d9ecf81d3cc3e0440cdb/w/1932456569dd6af304988df3/e/f934c5e8fb6d80de1dee92fe

Slicing directly from the STEP files usually produces the best results, but included STL files too.

Material: I used Polymaker PolyMax PLA but any PLA+ filament or other tough filament should do.

I used these print settings with good results:
Layer height: 0.2
Walls printing order: Inner/Outer
Wall loops: 6
Top shell layers: 13
Top surface pattern: Concentric
Bottom shell layers: 13
Bottom surface pattern: Concentric
Internal solid infill pattern: Concentric
Sparse infill density: 15%
Sparse infill pattern: 3D Honeycomb
Supports: Tree (auto). I painted additional support modifiers in crucial places. The auto support didn't fully support the bottom arc overhang on the grip, and supported a bit too much on the bridge inside the large hex holes in the end.

PET-bottle loop: Print it standing up on the flat little top, and use tree supports for the hexagonal hole to give the part some extra horizontal rigidity. Turn off Scarf join for this part or it might dislodge.