A Crankshaft is a way of turning Rotational Power into Moving-back-and-forth Power. This can be useful in order to power devices such as the Bellows, or Water Pumps.
The Crankshaft consists of two parts: the base, and the shaft. The base must be connected to an Axle, and devices can be connected to the end of the shaft.
Multiblock: tfc:crankshaft
A Crankshaft being powered by an Axle
The base can be crafted from Brass. Once a base is placed, a shaft can be added to it by using a Steel Rod on the base. If there is an empty space to the side of the crankshaft, the rod will be placed.
The crankshaft can be connected to a Bellows by placing one adjacent to the shaft. This will then push automatically every time the shaft extends then contracts. When connected to a crankshaft it cannot be operated manually.
The crankshaft can also be connected to a Pump, which can be used to transport fluids.