Handcranking

Handcranking is the manual operation of a device by turning a handle connected to a crankshaft to initiate operation. In engines, the handle engages the engine’s crankshaft and, through gearing, rotates the pistons until the engine can sustain combustion on its own. Handcranks were common before electric starters and were used on a range of machines, including automobiles, aircraft, generators, and various pumps.

Historically, automobiles often used a removable hand crank threaded into the front of the engine. The operator stood at the front, turned the crank to rotate the crankshaft, and then started the engine as soon as it fired. Similar devices were used on some aircraft and farm equipment. In modern machinery, most engines employ electric starters or alternative starting systems, with handcranking retained mainly for historical interest or specific, low-reliability contexts.

Operation and safety considerations are central to handcranking. Users should maintain a firm stance and keep both hands on the crank, with wrists straight and the body braced. It is important to ensure the engine is in neutral, the area around belts and pulleys is clear, and the crank does not slip. Avoid cranking with ignition on if a backfire is possible, as kickback can cause injury. The crank and handle can also suffer damage from improper use or overcranking.

Limitations and modern context: Handcranking is labor-intensive and slow, making it impractical for many modern engines, especially high-compression designs. While it reduces reliance on electrical power, it is largely replaced by electric starters, recoil systems, or other automated means in contemporary machinery. It remains a notable feature of early automotive and mechanical history.