One evening of CAD. One evening of CAM. One evening of CNC. And it fit together (quite well). This is just held together with precisely located wooden dowel pins. We will add screws tomorrow.
The only missing piece is the actual guide for running the blocks through. That is separate so that it can be “dialed in” to the perfect cutting depth.
Here is an action video of the [M003] Auto Loading Jig in action on our CNC router. Strong spring pressure is exerted on each wooden block up so the top of the block is always flat against the bottom of the Lexan panel on top. This results in consistent routing depth.
The Barrel Sander is coming along again, after a small detour to build the (M003) Auto Loading jig. Here is the nine sides bolted inside the barrel. They do three things:
- Make the barrel stronger so the wheels that it turns on have more support than just thin metal.
- Provide a disrupted circle which will cause the materials to actually turn instead of sliding.
- Protect the inside of the barrel from the sanding action.
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.
The cable winding pulley was the most complicated part of the machine due to it’s multiple set screws, flat surfaces, precise bore, and threading. One set screw holds the pulley on the shaft. The other set screw holds the cable firmly attached to the pulley.
Here is a picture of the pulley mounted to the DMM Tech Servo Motor. In the background you can see the cable go up through the top of the machine, over the free pulley, and back down to hold the main slider mechanism.