I have a lot of hard drives around my place. I'm less of an external enclosure guy and more of a bare drive in pelican case which I can hot swap kind of guy. Nerdy? Yes. Cheaper and cooler? Hell yes. Anyway, this is the mechanism of a 500GB Western Digital drive that had a disconcerting click when in use so was therefore retired from active service. Thought it would be fun to crack it open.
As always, click to enlarge.