MS21209F520L by HELI-COIL

The Heli-Coil MS21209F520L (Heli-Coil Part Number: 3591-5CNW625) is a high-performance tanged screw-locking wire insert engineered to establish high-strength, permanent internal threads in extreme structural applications. Precision-coiled from cold-drawn 304 stainless steel wire with a specialized diamond-shaped profile, this insert features an advanced internal design with straight, chordal locking segments. When mating hardware is introduced, these flat segments flex elastically to exert a consistent prevailing torque that prevents fastener backing-out, providing critical vibration resistance without the need for lock wiring or chemical compounds. Pre-finished with a specialized dry film lubricant, it significantly reduces installation friction, protects soft host materials from thread stripping, and ensures highly uniform torque-tension dynamics.

Internal Screw-Locking Profile Employs straight chordal segments on the locking coils that apply robust friction against the bolt threads to prevent loosening under heavy cyclic stress.

Integrated Driving Tang Features a heavy-duty installation tang on the lead coil, giving manual or automated tooling a secure anchor point for precise depth control.

Austenitic Stainless Steel Wire Formed from work-hardened corrosion-resistant steel to provide a wear-proof thread foundation that shields soft alloys from stripping, seizing, and galling.

Dry Film Lubricant Finishing Treated with a specialized dry lubricant layer that eliminates friction-induced wear during assembly and standardizes torque characteristics.