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It’s the inside of an old fashioned Cylindrical (planetary) pencil sharpener!”
Cylindrical Sharpeners
A larger, staยญtionยญary meยญchanยญiยญcal sharpยญener can be mounted on a desk or wall and powยญered by a crank. Typยญiยญcally, the penยญcil is inยญserted into the sharpยญener with one hand and the crank turned with the other. This roยญtates a set of heยญliยญcal cylinยญdriยญcal cutยญters in the mechยญaยญnism, set at a diยญvergยญing angle to each other. This quickly sharpยญens the penยญcil, with a more preยญcise finยญish than the simยญpler blade device.
Adยญvanced modยญels have a spring-driยญven holder for the penยญcil (the penยญcil adยญvances into the mechยญaยญnism while being sharpยญened). Some verยญsions also offer a regยญuยญlaยญtor of the deยญsired sharpยญness (it is not alยญways deยญsired to make the graphite core neeยญdle-sharp).
Such sharpยญenยญers may be very easy to use even by chilยญdren, but may be more exยญpenยญsive than prism sharpยญenยญers. Some such roยญtary sharpยญenยญers have only one burr cylinยญder. The casยญing of the sharpยญener is the reposยญiยญtory for the penยญcil shavยญings, and needs to be empยญtied peยญriยญodยญiยญcally. These mechยญaยญnisms are also called planยญeยญtary sharpeners, in refยญerยญence to their use of planยญeยญtaryโ gears.
Credit: wikipedia.com