Re: Cool Running
The trick worked on drives in the past because back then the bearings did wear out and increased tolerances together with less than stellar head positioning would lead to read/write failures.
not only that but there was also the protective coating on the platters that, in some cases, would soften from the heat of operation... when the drives spun down the heads would settle into the now soft coating... when the drive cooled off, those head were effectively cemented to the platters...
when the drive was powered back up, the heads would prevent the platters from spinning... this is where the quick spinning or light thumping would come in handy to pop the heads loose and let the drive platters spin properly... freezing the drive would, in many cases, allow the coating to shrink away from the heads so the platters weren't held captive when power was applied...
yes, sometimes a head might get torn off the arm it was mounted to... i'm sitting here looking at a clock made from an old ST-125 that had this happen... luckily it was the last head in the count that came off... luckily? yeah, because i low leveled the drive and told it it had one less head... yeah, that reduced the available storage space and the data was lost but it worked well enough for the tasks it had to do... that drive ran for another 5 years or so before being replaced by a larger drive and one that didn't have the sticktion problem...
since it was already damaged, i removed the cover to get at the insides... the bottom side of the bottom platter had a nice clean circle scrapped into it where the head had gouged out the material... i powered the drive and used a screwdriver to carefully scrap another circle for added decoration... then i removed the platter motor and replaced it with a clock work, figured out how to mount that one platter, and applied a ring of numbers along with some clock hands... the cover was replaced with a custom hand-cut plexiglass cover and boom! one hard drive clock was born :)
https://www.dropbox.com/s/rxtjboh29ee0a0b/st-125-hard-drive-clock.jpg?dl=0