ARP 200-8204 Self-Locking 12-Point Nut 3/8-24 Thread Reduced Wrenching

The ARP 200-8204 is a high-tech self-locking 12-point nut featuring a 3/8-24 thread and a reduced wrenching design. Built for high-stress, high-temperature, and severe vibration environments, this all-metal K-nut is engineered to maintain a positive lock without the use of nylon inserts or secondary locking devices — making it ideal for demanding engine and drivetrain applications.

The locking mechanism works through an elliptically offset upper portion of the nut. This controlled elastic deformation creates a consistent friction hold that securely locks the nut in place, yet allows it to be removed and reinstalled with standard tooling. Unlike nylon-insert locknuts, this all-metal construction makes the ARP 200-8204 suitable for elevated temperatures where plastic-based locking elements would fail.

Key Features:

• Thread Size: 3/8-24 (fine thread)
• Head Style: 12-point reduced wrenching
• Locking Type: Mechanical — elliptically offset (K-nut style)
• Material: Carbon-alloy steel
• Finish: Cadmium and chromate for corrosion resistance
• All-metal construction — temperature resistant, no nylon insert
• Lightweight design without sacrificing clamping integrity
• Almost indefinitely reusable without loss of locking effectiveness
• Sold individually (each)

The 12-point reduced wrenching head allows use in tight spaces where a standard hex nut would be difficult to access. ARP's all-metal self-locking nuts are trusted across racing, performance, and industrial applications where fastener reliability under extreme conditions is non-negotiable.