3D printers are all the rage these days, and are coming down in price gradually, but are still a bit out of reach for many.
So many capable electronics and maker hobbyists have turned to re-purposing all sorts of things to build their own 3D Printers on the cheap.
Here’s one great example (though he uses a number of prefab things like stepper motors, extruder nozzles, and Arduino boards).
The tutorial is in three parts, and is pretty complete, including showing how to program the Arduino, and actually use the printer to create parts. (Humorously, he actually uses the printer with temporary “duct tape and bailing wire” construction to make the last few printed parts brackets and then replaces them into the machine!)