After years of making the same part repeatedly on the CNC router, I finally decided it was time to make the router load it’s own material.
Friction is a valid way to hold a part for routing. That is how most vices and clamps work. The key here is to calculate an amount of friction that will resist the cutting forces while at the same time keeping it low enough for the router to be able to overcome it while loading and unloading.
I’ll post more on this when we have it working. For now, here is a cool picture of the jig.
The inside of the barrel tumbler needs a polygon (made from wood) in order to (a) give enough “traction” to turn the contents, and (b) protect the barrel from repeated impacts. I’m going to use Oak or Maple to do this. Based on the width and thickness of available material, I chose a 9-sided polygon.
Here is a picture of the CAM operation prepared using Fusion 360. I will make nine of these with just a fraction of an inch extra that I can remove on the jointer while getting a tight fit.