Installing Universal Lead Screw Assemblies

Lead Screw Assembly Components

Shaft Coupling

A flexible antibacklash coupling is needed between the drive motor and lead screw to isolate the motor bearing errors from the lead screw bearing. Metal bellows type couplings have been used successfully. Split clamps are recommended to prevent loosening by motor torque.


The lead nut requires proper lubrication for peak performance and longevity of the Universal lead screw assembly. Our B-3 lead screw oil provides the required boundary lubrication on the nut / screw interface, and offers excellent wear protection and uniform torque transition from static to dynamic conditions. The B-3 oil film must be periodically replenished, a procedure which may be accomplished by oil bath immersion, automatic application, or manual oiling on a maintenance schedule determined by the application parameters. Universal Thread's optional lubricator for the lead nut may be incorporated to extend the maintenance interval.

Universal Thread's own light grease, specified KS-46, provides exceptional performance in many applications. The KS-46's torque and wear characteristics are excellent, and required relubrication is less frequent than with oil.

Universal Thread has provided lubrication systems for special environments (e.g. vacuum, cryogenic, etc.). Please contact the factory with your special requirements.


The lead screw must be rigidly mounted precisely parallel to the direction of motion. The O.D. of the thrust bearing must be a sliding fit in its bore, and must be clamped axially only.

When the travel is six inches or less the thrust bearing provides adequate radial support, and a bearing at the outboard end may be omitted.

When the travel exceeds six inches, we recommend a radial bearing to support the outboard end. Free axial movement at this bearing must be permitted.

In every case, the nut clamp area must be fully and rigidly supported by the other slide member. Coaxial alignment of the clamp area with the lead screw must be preserved within 0.002".

Contact us to discuss your application or request a quote. We will help you specify the lowest-cost solution that will meet your requirements.