Dremel’s aren’t terribly expensive, but nothing beats the price of free, since chances are you already have all of this stuff laying around in a junk drawer.
This simple build uses a small motor, a 9 volt battery, a switch, and some hot glue to form the bulk of the tool. The cutting wheel is made from a repurposed bottle cap and a pen refill. It’s keen enough to cut through softwoods, but I wouldn’t recommend using it on metal unless you like having Coke cap shards in your eyes.
Contact the author at Bryan.Menegus@gizmodo.com.