crank (n.) Look up crank at Dictionary.com
Old English *cranc, implied in crancstæf "a weaver's instrument," crencestre "female weaver, spinster," from Proto-Germanic base *krank-, and related to crincan "to bend, yield" (see crinkle, cringe). English retains the literal sense of the ancient root, while German and Dutch krank "sick," formerly "weak, small," is a figurative use.

The sense of "an eccentric person," especially one who is irrationally fixated, is first recorded 1833, said to be from the crank of a barrel organ, which makes it play the same tune over and over; but more likely a back-formation from cranky (q.v.). Meaning "methamphetamine" attested by 1989.
crank (v.) Look up crank at Dictionary.com
1590s, "to zig-zag," from crank (n.). Meaning "to turn a crank" is first attested 1908, with reference to automobile engines. Related: Cranked; cranking.