One of the most interesting and useful things about 3D printers is that they’re meta-tools — tools that can be used to make new tools.
I recently needed to adjust the suspension on the e-bike I’m building, but found it quite awkward to turn due to a combination of spring stiffness, inaccessibility, and small diameter. It would be difficult to get slip-joint pliers around it, and turning it by hand wasn’t feasible.
After a few quick measurements, I drew up a first draft of a bit to fit over the adjustment nut. This took a few iterations to get right due to the unusual shape, but eventually I had an outline that would fit over the nut.
I added a handle to turn the current design into a wrench, printed it, and tried it out. It fit, but the force needed to turn the nut immediately bent the plastic out of shape. Version 1.0 looked like the right tool, but needed to be much stronger.
Keeping the center free to slip around the shock absorber body, I added as much material as possible and printed the resulting model at 80% infill with four outer shells. This did the trick, and the resulting wrench is usable enough that it’s going in the bike’s tool bag.
