MS21209F410L - Screw Threaded Insert by Helicoil Stanley Engineered Fastening

The Heli-Coil MS21209F410L (Heli-Coil Part Number: 3585-4EN410) is a military-standard screw-locking wire thread insert engineered to establish high-strength, permanent internal threads in critical aerospace and high-vibration applications. Precision-coiled from cold-drawn 304 stainless steel wire with a specialized diamond-shaped profile, this tanged insert features internal locking coils with straight chordal segments. When mating male hardware is installed, these flat segments flex outward to exert continuous prevailing torque onto the fastener threads. This design provides exceptional vibration resistance, preventing rotational loosening under severe dynamic shock while shielding soft parent materials from internal thread stripping, galling, and wear. Pre-coated with a specialized dry film lubricant, it stabilizes installation torque and ensures consistent clamping force.

Internal Screw-Locking Profile Deformed chordal coils apply continuous prevailing locking torque to keep mating hardware firmly secured against extreme operational shock and rotational vibration.

Standard Driving Tang Engineered with an integrated drive tang on the leading coil to ensure positive tool engagement and precise insertion depth control.

Austenitic Stainless Steel Construction Crafted from work-hardened, corrosion-resistant steel wire to establish a wear-proof thread foundation that protects soft parent materials from stripping.

Dry Film Lubricant Coating Factory-applied dry film lubrication stabilizes installation friction, prevents thread galling, and maintains consistent torque-tension relationships.