3591-4CN500 - Helicoil ® Threaded Insert by Stanley ® Engineered Fastening

The Heli-Coil 3591-4CN500 is a high-strength screw-locking wire thread insert designed to establish secure, permanent internal threads in light metals, aluminum, and composite host materials. Precision-coiled from cold-drawn 304 stainless steel wire with a diamond cross-section, this tanged insert features internal locking coils with straight chordal segments. When male hardware is driven in, these flat segments flex outward to exert a continuous prevailing torque onto the fastener threads. This provides exceptional vibration resistance, preventing rotational backing-out under extreme dynamic shock while protecting parent materials against internal thread stripping, galling, and wear. Pre-coated with a specialized dry film lubricant, it stabilizes assembly friction and ensures consistent clamping force.

Internal Screw-Locking Profile Engineered chordal locking coils apply continuous prevailing friction to hold mating screws firmly against severe operational shock and dynamic vibration.

Integrated Driving Tang Features a precision drive tang on the leading coil to provide positive tool engagement and accurate, repeatable insertion depth control.

304 Stainless Steel Construction Cold-drawn from work-hardened austenitic stainless steel wire to build a corrosion-resistant internal thread foundation that shields soft alloys from stripping.

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