Unifix Nylon Insert Nuts - 1.1/2-12 - Silver

Generally, it is recommended to use new nylon insert nuts for critical applications, as the nylon ring deforms during the first installation and provides less locking force upon subsequent uses.

This is the sizing convention where 1.1/2 inch is the nominal diameter and 12 refers to the number of threads per inch (TPI) for the UNF (Unified Fine) thread standard.

Usually, no. The built-in nylon insert is designed to provide the necessary friction to prevent loosening, making secondary liquid thread-lockers unnecessary in most standard applications.

The silver finish provides corrosion resistance, making them suitable for many outdoor environments, though they should be protected from harsh chemicals or direct saltwater exposure to maximize their lifespan.

The nylon insert can begin to soften or lose its elastic properties at temperatures typically above 120°C (approx. 250°F), so they are not recommended for high-heat engine exhaust applications.

Verify the bolt thread pitch is exactly 12 TPI. Resistance is expected when the bolt contacts the nylon insert, but if it is impossible to turn, check for thread damage or debris.

Ensure the nut has been tightened far enough so the bolt threads fully engage the nylon collar. If the bolt is too short to reach the collar, the locking feature will not activate.