The IBM 729 magnetic tape drive was the mainstay mass data storage component of IBM computers from the late 1950s through the mid 1960s. When a movie or television show of the era wanted to show a computer, you’d usually see the jerky, staccato motion of the tape reels on one of these units. To provide rapid access time, the tape was buffered in vacuum columns, with the reels servo controlled to maintain the loops in the columns within limits. The reels, in turn, were driven by powerful constantly-turning motors for forward and backward motion belt-driving magnetic clutches which coupled them to the shaft holding the reel.
But what do you do when the clutch fails? Just like your 1959 Ford Fairlane three on the tree, you do a clutch job, tearing it down and rebuilding it!