At the most basic level, most shop tools are just a motor with the right attachments. But the details are often far from simple. [DuctTapeMechanic] took a junker clothes dryer, yanked the electric motor from it, and converted it into a disk sander. The price was right at about $10. You can see it all after the break.
As you might imagine, having the motor is only half the battle. You also need a way to mount the thing securely and a way to affix the sanding disk. While this doesn’t pose the same challenges as, say, a drill press, it does take some thought. The motor in the donor dryer didn’t have threads on the shaft, so a bolt and some welding time took care of that. We suspect that’s tricky because you need the shaft and the bolt to be concentric and level.
Once you have a threaded shaft, the rest of the build is anti-climatic. A little carpentry and a little electrical. We would probably cover up the electrical connections a bit more. It seems like you’d want to know which way the motor spins so you could use a reverse thread, if necessary. From the video, we think the motor he has was spinning the right way, but we don’t know if that’s always true.
There’s something satisfying about building your own tools. If you work on smaller things, we’ve seen a miniature sander that might be handy to have around. If you want to go the other way, try finding an old floor polisher instead of a dryer.