Self-locking Nut Prevailing Torque Testing Machine

Servo torsion test bench for prevailing torque nuts, used for testing prevailing-on torque, prevailing-off torque and repeated locking performance of self-locking nuts

Product Overview

This self-locking nut prevailing torque testing machine adopts high-precision servo torsion drive system, specially developed for all-metal self-locking nuts and non-metallic insert prevailing torque nuts. It can complete prevailing-on torque test, prevailing-off torque test, repeated assembly and disassembly locking torque test and torque-clamp force combined test. The equipment can record the torque change curve during multiple screwing in and out, detect the attenuation of locking performance, and verify whether the nut meets the functional requirements of prevailing torque fasteners. Equipped with standard test bolts and replaceable positioning fixtures, it can ensure coaxiality during testing and reduce extra bending stress. The supporting software collects torque and angle data in real time, automatically identifies peak torque values and exports standardized test reports. It is suitable for incoming inspection, new product development and performance verification of self-locking nuts.

Applicable International Standards

The system is designed to comply with the following recognized testing standards:

• ISO 2320:2015 — Fasteners — Prevailing torque steel nuts — Functional properties
• ISO 16047:2005 — Fasteners — Torque/clamp force testing
• ISO 898-2:2012 — Mechanical properties of fasteners — Nuts with specified proof load values

Note: Specific compliance depends on model configuration, torque sensor selection and customized fixture design. Customized fixtures and test schemes for extra testing standards are available upon request.

Key Features

• High precision servo torsion drive — Smooth and uniform loading, stable for repeated screwing test of self-locking nuts.
• Wide optional torque range — 0.01 ~ 200 N·m, multiple sensors optional, match M5~M39 nuts.
• Multi-test mode integration — Prevailing-on torque test, prevailing-off torque test, repeated locking cycle test, torque holding test.
• Modular test bolt fixtures — Interchangeable test bolts and positioning seats, ensure coaxiality of nut assembly.
• Rich calculated indicators — Screwing-in torque, unscrewing torque, torque attenuation, peak torque and torque-angle curve.
• Real-time curve display — Torque-angle curve, torque-time curve displayed synchronously during testing.
• Professional test software — Automatic peak value capture, batch data storage and formatted test report export.
• Complete safety protection — Over-torque, over-angle, overload and emergency stop protection functions.

Technical Specifications

Specifications vary by model configuration, torque sensor selection and customized fixture. Micro torque version and aerospace special nut fixtures can be customized on request.

Typical Applications

• Fastener manufacturing — Batch inspection of prevailing torque performance for nylon insert and all-metal self-locking nuts.
• Automotive component sector — Verification of locking torque of self-locking nuts used in chassis and suspension assemblies.
• Mechanical equipment industry — Functional test of anti-loosening nuts for engineering machinery and transmission parts.
• Fastener R&D laboratory — Study of torque attenuation after repeated assembly and disassembly of self-locking nuts.
• Third-party testing institutions — Standard prevailing torque test and certification service according to ISO 2320.