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.
Working on another machine to speed up yet another tedious workshop process. Think of it as a special router table that takes 2 routers set to 45 degree angles. The guide (not shown) will allow precise alignment of the work piece AND cover the cutters to prevent injury.
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.
All of the parts are getting into final position. Getting ready to build it!
Most standard 60HZ AC motors come in approximately 3600 RPM or 1800 RPM. The barrel sander needs to spin at about 30 RPM. To achieve this, the following approximate pulley sizes will be used:
- 1800 RPM motor
- Shaft to 2″ Pulley
- Belt to 7.5″ pulley
- Shaft to 1.75″ pulley
- Belt to barrel (approx 23″)
- End Result is approx 30 RPM
(This was from memory so might be fractionally off).
Here is a render of the pulley assembly (draft):
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.
Machine M002 is in the works. It is a barrel tumbler for wooden parts. This project will allow us to knock sharp edges off of small wooden products by the hundreds at a time. More to come!