the.com/crankshaft
The iron spine that turns your engine's up-and-down tantrums into forward motion.
means A rotating shaft that converts the pistons' straight-line strokes into the spinning power that drives the wheels.
from From crank, an old Germanic word for something bent or twisted, married to shaft — literally the bent rod.
CounterweightsBalance weights stop it shaking itself apart.
Throw distanceIts offset sets the engine's stroke length.
Forged strengthOften forged from one solid steel billet.