We recommend the following methods for preventing the rotation of the lifting screw on standard screw jacks. For multiple screw jack systems, fix the lead screw end fittings (e.g. top plate or clevis) to the common member being lifted by all the units. For single screw jack applications, bolt the lead screw end fitting (e.g. top plate or clevis) to the load and ensure the load is guided to prevent rotation.

A guided load is always recommended to ensure that the screw jack does not receive any side load and so guidance can be scaled suitably for the load without altering the screw jack design unnecessarily. It should also be noted that an external guidance system can provide a higher restraining “key” torque than compared to an anti-rotation mechanism in a screw jack.