Using parts from HDD, I have created a spinner that spins a disk, coating PCBs or other flat things in a somewhat even coat of liquid. It is also can be used as a magnetic stirrer by using the magnet from the HDD. The unit uses the brushless motor from HDD to spin the disk. Since the unit does not need to have a lot of torque, this motor is perfect as it can spin at high speeds (depends on the motor driver and HDD type).
It can be used for a different purpose, it is just depended on the disk.
Coating stainless steel did not work well but looks cool. Coating silicon wafers work well (if the wafer can fit) because of the smoothness of the surface
Parts Link: http://www.thingiverse.com/thing:1665202
1. HDD brushless motor (assuming it’s the same dimensions as mine)
2. Motor controller (http://www.ebay.com.au/itm/SUPPO-50A-brushless-motor-speed-controller-/282089041823?hash=item41add12f9f:g:WjcAAOSw3xJVYrya)
3. PLEX control unit (see https://tinkersprojects.com/project/plex-controller/)
4. power plug
with the motor controller, if the motor runs for too long then the motor controller will need a bigger heatsink to help it stay cool and not melt the case. I have not put any air hole in the case or put and heat sink on due to I’m not running it for too long at a time.