The machine screw jack uses an machine threaded screw that is completely self-locking, meaning it will hold its position without a brake mechanism or locking systems. Ball screw jack use ball screws and ball nuts to convert rotary motion to linear movement, and require approx. 1/3 the horsepower compared to a machine screw jack. Due to the efficiency of the ball screw, brake mechanism must be used to stop and hold the lifting screw in position. Brake mechanism is also recommended for use on any screw jack if vibration is present.