The MS21042L06 is a military-standard all-metal self-locking reduced hex nut used in aircraft structural and mechanical assemblies. It is designed to provide secure fastening in high-vibration environments without the use of a nylon insert, making it suitable for higher temperature applications compared to standard locknuts.

This nut features a compact, reduced-hex profile and an all-metal prevailing torque design that maintains clamping force under cyclic loads. It is commonly used in airframe structures, brackets, equipment mounting points, and control system assemblies where reliable locking and long-term durability are required.

Manufactured to MS specifications, it is typically made from cadmium-plated steel with dry film lubrication to reduce friction and prevent galling during installation. It is widely used in both fixed-wing and rotary aircraft applications.

Key features include:

MS21042L06 military standard self-locking nut
Reduced hex, low-profile design
All-metal locking (no nylon insert)
Suitable for high-temperature environments
Used in airframe and mechanical assemblies
High resistance to vibration loosening
Cadmium-plated steel construction
Dry film lubricated for smoother installation
Supports cyclic load and aviation service conditions
Direct replacement per MS aircraft hardware standards