Wood splitters work by using a hydraulic pump to drive a wedge through a length of firewood. Depending on the shape of the wedge, the log splits into two or four pieces. The pumps on some splitters depend on manual operation or electric motors, but most use a gasoline engine.
The operator of the log splitter controls the action with a lever that connects to a spool valve. The valve directs high-pressure hydraulic fluid to push the wedge forward or low-pressure fluid to pull it from the wood.
A typical wood splitter features a 5-horsepower four-cycle gasoline engine to operate the pump. Wood splitters for residential use typically produce between 12 and 20 tons of force on the wedge to drive it through the log. Commercial units operate in the 20- to 30-ton range.
With manual log splitters, the operator pumps a lever to create the hydraulic force to drive the wedge through the wood. These machines work like hydraulic floor jacks.
Operators of log splitters should always observe safety precautions, such as wearing eye protection and gloves when operating the machine. They should wait until the unit retracts fully before removing split firewood or adding another log to the machine.