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Crank Puller, Crank Extractor
From WikiPedalia
Tool for removing cotterless cranks. A crank puller consists of a "nut" part which screws into the dust-cap threads of the arm, and a "bolt" part that fits through the "nut" part and presses against the end of the bottom bracket spindle, so the "nut" part pulls the arm off. Some crank pullers have a handle attached to the back of the "bolt" part, others require the use of a separate wrench to turn the "bolt" part.
See also my "Tooltips" article on Cotterless Crank Removal.
