PSM Prevailing Torque Nuts are spring steel fasteners engineered to maintain a locking force on screws even under vibration, thermal cycling, or repeated use. Unlike standard nuts that rely solely on friction, prevailing torque nuts incorporate built-in locking features (e.g. deformation, interference, or spring action) that resist loosening. In assemblies combining plastic panels or mixed materials, these nuts help secure joints without needing additional locking hardware like washers or adhesives.
Advantages
> Higher installation torque than conventional U-Nuts
> High vibration resistance
> Screw will not loosen even in low torque applications
> Non-paint clogging
>Reusable
MATERIAL
CS50, CS60 carbon steel, austempered
METHOD OF ASSEMBLY:
Exactly the same as conventional ‘U-Nut.
WHEN SPECIFYING, PLEASE STATE:
- Quantity
- Prefix (CBTN)
- Part No.
- Finish code (e.g. 14000 CBTN-0361-08)
Key Features
Self-locking action: Through interference or spring action, the nut provides resistance to turning, which helps prevent fasteners from vibrating loose.
Reusable locking capability: Many prevailing torque nut designs retain some of their locking ability over multiple assembly cycles.
Compact and efficient: Because the locking mechanism is integrated into the nut, external locking components are often not needed, saving space and reducing parts.
Temperature and vibration resilience: The spring steel design maintains preload and locking under dynamic conditions and thermal expansion variations.
Compatibility with plastic hosts: When used in plastic or plastic-metal hybrid assemblies, they can reduce the risk of stress on the plastic by localizing locking forces.
Design & Specification Guidelines
Nut / Locking Type & Geometry
Some prevailing torque nuts use a top flange with interference, others a deformed thread segment, and yet others a spring tab or camming surface. Choose the style appropriate to your assembly needs.
The amount of interference or spring deformation should be controlled so as not to overstress mating parts or cause excessive insertion torque.
Material & Finish
Spring steel (e.g. CS60 / CS70) is commonly used for the nut body and locking features.
Surface coatings (zinc plating, passivation, or low-friction finishes) help control friction, reduce galling, and protect both the nut and screw threads.
Panel & Host Design
The panel or substrate must be stiff enough to support the forces transmitted by the prevailing nut without undue deflection or damage.
In plastic regions, reinforce with ribs or thicker materials to avoid stress concentration near the nut area.
Dimensional Data & Sizes
Dimensions in millimetres