After finalizing the CAD for our weapon’s bevel gearbox, we decided to make a prototype gearbox to make sure the 2x3x2.5″ profile is achievable and our components work together. Since we did not have actual components (due to SORF lead times), we had to make some substitutions. Our rectangular stock was cut from leftover aluminum stock on the waterjet (then milled to match our CAD), and our bearings were substituted with turned plastic bushings. We then 3D printed a couple of pulleys to determine the pulley shape & belt size requirements.
We learned a lot from our gearbox prototype, and should be in good shape moving forward. Some major takeaways from the project:
- The 2×3″ form factor is achievable, but does not leave much margin for adjustment
- Aluminum appears to be more than strong enough for the gearbox frame (this saves a quarter pound from our original steel design)
- The gearbox can be assembled in place
- The waterjet adds a significant and non-uniform draft
- Maintaining a consistent homing point for bringing into square
Over the next couple weeks, we should be able to swap out components for their real counterparts as they arrive and begin machining the final gearbox.