You have a 3D Printer, or maybe you want a 3D Printer. Maybe the only thing stopping you from acquiring a 3D Printer is that your significant dearest is unconvinced of your NEED for a 3D Printer. And if you're really lucky, maybe the dial on the clothes dryer has just broken. Well if you need help showing that your desire to pull physical objects out of thin air like Marry Poppins's carpet bag is justified? Perhaps you should read further.
Step 1: Identify Household Need
In this case the household need is a broken dial on the clothes dryer.
As you can see, the inside of the dial has snapped off allowing the dial to turn freely without turning the shaft. It is arguably a design prone to breaking, lets see if we can fix that.
The shaft that needs to turn is a standard flatted shaft.
Step 2: Design The Fix
Using some pliers I removed the rest of the broken plastic from the broken dial.
Then, using my trusty digital calipers and measurements jotted down on a notepad I moved on over to the computer and opened up Google Sketchup. Basic 3d modeling can be learned easily and acquainting yourself with a couple of the free modeling tools available is a must. I would recommend looking at Sketchup for quick, visually simple objects, Blender for organic shapes and OpenSCAD for procedural step by step designs (objects are modeled using basic scripting or programming).
This is shape that is needed to fit in the broken cavity to mate the dial back onto the flattened shaft.
Using Google's handy pull to tool I extrude outwards into 3d dimensions by 12mm, select the object, and export as an STL.
Step Three: Print the Repair Part
I opened up the STL in the slicing tool replicatorg and the instructions for the 3d printer are generated. Now to push the magic 'build' button and wait about 10 minutes.
There it is, happily creating something from nothing in Glow-in-the-Dark ABS. Granted Natural ABS would have been the cheapest option but as this filament was already primed in the hotend and it was such a small piece it wouldn't have been worth swapping plastics.
It's finished! (never-mind the poorly laid Polyimide Tape on the print-bed, I had just removed a stuck fast glow in the dark flying saucer)
Step Four: Make the Repair
The printed repair piece fits perfectly!
Success! The dial has been repaired. Peace is restored to the household and the children will be cleanly dressed one more day.
Thank you 3D Printer.