forearm massager for climbers (and keyboard users)

OK. the link here to keyboards is probably even more tenuous than my bluetooth scale but whatever. In the quest to relieve perpetually tense forearms due to bouldering + heavy keyboard usage I came up with this massager using easily obtained components. The total parts list with estimated price: (all items except for skateboard wheels were obtained at Lowe's)




4 skateboard wheels with bearings: $10 at target, but you can easily wind up spending far more for fancier wheels like the 70mm kryptonics wheels in most of these pictures.

2 4" wood clamps: 2@ $4.99 ea. = $9.98
2 5/16" x 8" machine bolts: 2@ $1.15 = $2.30
3 11"x1/4" threaded rods: 3@ $0.97 = $2.91
8 plastic spacers: 4 x (2 @ $1.09)= $4.36
2 pieces of thicker(1.5"x1.5"x8") wood: ? this was just scrap wood I had lying around, not sure how much it would cost.
(optional) 1 piece thinner wood (0.75"x1.5"x8") also scrap wood and not really necessary, just added to allow clamping in one other place.

4 pieces of 1/4" thick ABS plastic: ? scrap plastic I had lying around, not sure how much it would cost but small sheets of lexan or acrylic at Lowe's are pretty cheap.


Assembly:

Putting things together is pretty easy: thread one wheel onto one of the 8" bolts, followed by 2 plastic spacers.



Next, add another wheel followed by two more spacers and a piece of ABS plastic.