Disclosed herein is a portable wood log splitter comprising a power unit and a work tool. The power unit comprises an engine and a gear box while the work tool comprises a drive shaft having a spreading mechanism and a splitting threaded cone. In some embodiments, the work tool is releasable from an output shaft of the gear box. The drive shaft of the work tool is hollow and provided with a thread on the outer circumference to drive the spreading mechanism. A nut with a toothed disc resides on the thread and able to shift in the axial direction of the drive shaft rotation axis due to rotation of the drive shaft. In operation, the splitting threaded cone is driven by force of the power unit to initially fracture a log, then using the spreading mechanism, the portions of the split log are fully separated under power.