Abstract: A portable sawmill is constructed to produce dimensioned lumber from logs in remote logging locations. The portable sawmill employs but a single, disk shaped rotating blade which is powered by a relatively low horsepower engine. The engine and blade are mounted upon a carriage which traverses the length of a log to effectuate first a horizontal cut and then a vertical cut with a single saw blade in returning along the length of the log. The blade is oriented for vertical cutting as it progresses along the track away from the operator. The orientation of the blade is automatically reversed at the remote end of the log. The saw blade then cuts the log while in a horizontal orientation as it returns to the operator position. The maximum speed of longitudinal traverse of the carriage is separately adjustable for both vertical and horizontal cuts.