Rack and Pinion Fidget Toy
NOTE: To complete this toy you will need a length of 1/4 inch dowel, or other such rod measuring .25" or 6.35mm in diameter. All other components are 3D printable.
This is a model of an old device which turns constant rotary motion into back and forth motion. The device can be found in 507 Mechanical movements here: http://507movements.com/mm_114.html
Here is a video about how I modeled this toy in Rhinoceros 3D: https://youtu.be/aDYaTnC2fpg