Reciprocating Drive Fidget.
Bill of Materials:
1 Handle (support touching build plate)
1 Piston Guide
2 Pinions (support touching build plate)
2 Pinion Caps
2 Piston Caps
I recommend print the pinions before the gears, and measure across the pinion gear teeth. It is supposed to be 14mm, but it ends up being 13.8mm on my printer. There are four options for the gear with different pinion hole sizes. I'd choose the one that is 0.1mm larger than the actual pinion gear size.
After verifying the assembly, I used epoxy glue to make it permanent.
Printed in PLA.