This is an idea that I came up with while taking apart old hard drives for fun. It turned into a regular thing and now I've got the process down to a science. Here's how I do it. I also sell them at http://www.etsy.com/shop/Yooderstuff
For this Instructable, I'll be using an old WD Caviar hard drive. Drive designs differ, and some are better for this project than others.
You will need:
Torx-6 and Torx-8 screwdrivers
Phillips head screwdriver
Drill and bits
3/4" clock movement
Next, undo the screws around the edges that hold the cover down, but don't go tugging yet. There is at least one more screw hiding under the stickers. One in the center, and one off to the side. Refer to the pictures to get an idea of where it'll be. Feel around and then cut through the stickers to get to the screws.
Once you've gotten all the screws, you can cut through the tape around the edge and open it up.
Step 2: Disassembly
Now it's time to free up the actuator. To do this, remove the two screws securing the top magnet, and remove it with a pair of needlenose pliers. Don't try it with your fingers. It won't work. Place the magnet far away from anything electronic.
Then, remove the single screw keeping the actuator retainer in place. Work the retainer up and out. The arm should swing freely now.
Now, undo the screws holding the platters down. You may have to hold the edges of the platters to keep them from spinning. Once the screws are off, turn the drive upside down on a soft cloth and the retainer, platters, and spacers will fall out neatly. Leave them alone, in that order.
Next, unscrew the motor assembly and pop it out.