Ultimate Scotch Yoke Mechanism (Print in Place)

This Scotch Yoke Mechanism turns simple rotation into smooth back-and-forth motion, letting you watch a spinning input convert into a perfect straight-line push. The mechanism works when you twist the knurled knob, driving a pin that rides inside the yoke's slot and forces the crossbar to slide back and forth, translating that rotary motion straight into linear motion. Getting a scotch yoke to print fully assembled isn't something I've seen done before, so I had to design many extra components that make it actually work, letting everything spin freely while still printing as one piece. Every joint was carefully tuned so the pin glides through the slot without binding, keeping the motion buttery smooth at any speed. It comes off the build plate already assembled, however there is a small custom support piece on the output rod that you can easily remove. The knurled grip on the knob and the geometric patterns across the fidget add a nice tactile detail while giving you visual confirmation of the spin. This one's a great pick for makers who love seeing real mechanical engineering play out in their hands.

Printing Instructions:

1. Prepare the Print Bed
   • Clean the print bed thoroughly with isopropyl alcohol to ensure proper adhesion.
   • Additional adhesive for the print bed is highly recommended! I suggest using 3D-Lac spray or a glue stick.
      
2. Download the Print Profile
   • Send the pre-configured print profile to your Bambu Lab printer through the Bambu Handy app or Download and open the pre-configured print profile in Bambu Studio.
      
3. Select Your Printing Options
   • Choose your filament type and color.
   • Select your print bed type (e.g., textured or smooth).
   • Confirm your printer settings, ideally for a Bambu Lab printer.
      
4. Start Printing
   • Begin the print job. No supports are necessary.