I wanted to way to control my propane tank from the front of my BBQ. Here is the new knob I installed on the front of the grill. Behind it you'll find parts from a weed whacker I found in the garbage.
Step 1: Salvage Weed Whacker Parts
I found this part of a weed whacker in the garbage. I needed the flexible driveshaft inside of it. It was more difficult to remove than I was expecting, I had to break a few nuts and bushings to get it out.
Step 2: Design the Parts
I started by modeling the existing propane knob in Fusion 360, then the parts I'll need to 3D print to complete this project. I decided to keep it simple, using 3 wedges to attach the parts to the propane tank.
Step 3: Test Fit and 3D Print Parts
I printed a few layers of my knob shape to make sure it fit. Nailed it on the first try! I printed the prototype parts quick and dirty. Here's what it looks like on the inside.
Step 4: Installed on Tank
Step 5: Drilling and Installing Grill Knob
I drilled a 1/4" hole needed to feed the flexible drive shaft through. There was a spring inside the weed whacker housing that fit my knob perfectly. It firmed things up a bit.
Step 6: Finished and Working!
The prototype worked so well that I just left it. My intentions were to revise the design and then print in ABS to withstand the heat of the grill. So far the heat has not affected the parts in any way. When it works, it works!