From syn2cat - HackerSpace.lu
 Why do we have a stock of old broken harddisks?
Those harddisks are a treasure of raw material for your projects. The following uses have been found:
- the head motor has strong magnets. Have fun with them or use them to fix something solidly to a metal surface. These magnets are used for:
- Caution: those magnets can be awfully strong, the bigger and older the disk the more force is in the magnets. Don't get your fingers pinched. Also don't make the magnets snap together as they are made of ceramic and will beak. In fact they will kind of explode into pieces.
- the platters are nice and shiny
- Cut them and use as laser reflectors. Yes, perfect surface.
- Build a windchimes out of them
- rings between platters
- also cool on windchimes
- keep a roll of paper rolled up
- the head motor solenoid has between 8 and 20 meters of very thin isolated wire. This wire is used here:
- solenoid for OpenDuino's badge reader
- wiring for the door and alarm status detectors
- strings of the windchimes
- if you don't rip everything apart you can use the head motor as galvo for a laser show
- a lot of screws
- the disc motor is usually a nice brushless type
- the motor can be reused if you either keep the controlling board or build your own circuit to drive it
- the base plate with motor is used as ball bearing of the rotating Cortana antenna