Comparing Prevailing Torque Locknut Designs

The following table compares the characteristics of five common prevailing torque locknut designs, outlining their best-fit applications, disadvantages, and performance across prevailing torque consistency, reusability and temperature limits.

At a Glance

Security Locknut

Main Advantages Consistent prevailing torque, high reusability, high-temperature capacity and locking mechanism is separate from clamp load

Prevailing Torque Consistency Highmaintains consistent prevailing torque through repeated use

Reusability Excellentdesigned for repeated installation and removal

Temperature Limits Suitable for temperatures from -30C to 300C

Special Tools Required None

Best-Fit Applications Mission-critical, high-vibration joints that are inspected, removed and reinstalled

Main Disadvantages Higher initial cost than conventional locknuts

Nylon-Insert Locknuts

Main Advantages Low cost, simple installation, widely available and effective for general-purpose applications

Prevailing Torque Consistency Moderatedecreases as the nylon insert wears

Reusability Limitedprevailing torque decreases with reuse. Effectively one time use.

Temperature Limits Limitedthe nylon insert can soften or become damaged at high temperatures

Special Tools Required None

Best-Fit Applications Install-and-forget, low- to moderate-vibration assemblies.

Main Disadvantages Nylon wears over time and is unsuitable for high-temperature applications

Split Nuts

Main Advantages Adjustable locking force, reusable and suitable for all-metal, high-temperature applications

Prevailing Torque Consistency Moderatedepends on maintaining pressure between the threaded sections

Reusability Moderatelocking force may diminish with wear

Temperature Limits Nonesuitable for high-temperature applications

Special Tools Required May require adjustment tools depending on design

Best-Fit Applications Adjustable industrial joints with periodic maintenance and moderate reusability

Main Disadvantages Locking force can decrease as components wear or require adjustment. Vertical split nuts often damage threads on bolt.

Deformed-Thread Nuts

Main Advantages All-metal construction, suitable for high-temperature applications and strong prevailing torque consistency

Prevailing Torque Consistency Moderate to highdecreases as the threads wear, hard to maintain a specific PT.

Reusability Effectively one-time use

Temperature Limits Nonesuitable for high-temperature applications

Special Tools Required None

Best-Fit Applications High-temperature, all-metal applications with occasional removal

Main Disadvantages Threads wear with repeated installation and removal

Adhesive Patch Nuts

Main Advantages Pre-applied locking mechanism, simple installation and suitable for automated or high-volume assembly

Prevailing Torque Consistency Moderatedecreases as the patch material deteriorates

Reusability Effectively one-time use

Temperature Limits Limiteddepends on the type of adhesive and nylon softens at high temperatures

Special Tools Required None

Best-Fit Applications Low-cost joints that won't be disassembled

Main Disadvantages Patch material deteriorates over time, with reuse and unsuitable for high-temperature applications

Why Engineers Choose the Security Locknut

In critical applications where maintaining consistent torque and tension are necessary, some industries establish performance requirements for prevailing torque locknuts

For example, New York City Transit requires prevailing torque locknuts to be installed and removed five times consecutively, measuring the torque after each cycle to ensure it stays above the minimum on the fifth removal. This demonstrates the locknut's locking ability after repeated use and eliminates most other prevailing torque locknuts.

The Security Locknut is the optimal choice in these industries for its ability to retain prevailing torque. Speak with one of our engineers to learn more about our design or get a quote today.