Abstract: The invention relates to a portable sawmill, in which the functions of adjusting a cut, and of making a cut, are divided between two separate devices, instead of combined in one device. The sawmill utilizes a chainsaw that is clamped to a carriage which is movably attached to an alignable monorail track. Attached to the track is a system of sprockets and a chain operated by a crank which moves the carriage back and forth on the track. Attached to the carriage is a throttle actuator that, in conjunction with the chain, operates the throttle of the chainsaw, so that the motor of the chainsaw is at full power when cutting, but returns to idle when not cutting. With the addition of a spacer to give clearance for the wheels of the carriage, the foregoing device can be attached to any suitable support, and then a log can be placed and held in position, and lumber cut from it. A suitable support can be the frame specifically designed for the invention, or the edge of a flat platform, such as a loading dock.