Try to follow this video with one: https://www.youtube.com/watch?v=GuIkvUTxYdU But be extremely careful with HDD magnets. Thy could produce dangerous "shrapnel" on contact with another one (there are two inside). Also, if you expose the dark metal under the shiny shell - paint it with nail polish as its dust is carcinogenic. And keep other compasses far enough away to avoid their accidental exposure to the mag.field.