Cranks and Screws

Some prison administrations felt that having inmates occupy the same space to work a treadmill or pick oakum was too much mingling. When they wanted to keep them properly isolated, inmates had to do work alone in their cells. Officials had also noticed something they found very interesting: Inmates hated a pointless task more than a meaningful one. This presented them with an obvious solution: the crank.
The crank was literally a crank that stuck out of a small wooden box that was usually set on a table or pedestal in the inmate’s cell. Despite its innocuous description, it was a truly soul-crushing monstrosity designed to exhaust inmates mentally and physically. Inside the box was a drum or paddle that turned nothing but sand and rocks. The axle on which the crank turned had a screw, which warders could tighten or loosen depending on how much punishment they wanted to mete out. The screw would make the crank easier or harder to turn.
Warders who came in to adjust the screw earned themselves the nickname “screws” for the suffering it caused.

A prisoner left in isolation with the crank usually did not need to worry about a beating if they just ignored the machine. Instead, they would worry about starvation. Each crank had a counter on the box that logged the number of turns. An inmate had to reach a certain number of turns before being allowed to do basic things like eat and sleep. Most were expected to make at least 10,000 rotations a day.