Heli-coil 3591-3CN380S Screw-locking Insert 10-32 Unf

Product Description

The HELI-COIL 3591-3CN380S is a tanged screw-locking helical wire insert designed to create vibration-resistant, threaded repairs and new thread installations in parent materials that require a secure hold. Built from Grade 304 stainless steel, this insert resists corrosion and handles elevated temperatures without losing clamping performance. It carries a 10-32 UNF thread profile and measures 0.38 inches in overall length, representing a 2D length-to-diameter ratio. The free-running coil engages a locking section that grips the mating fastener and resists back-out under load. Machinists, maintenance technicians, and industrial assembly professionals install this insert where thread stripping, fatigue, or galling in softer parent materials would otherwise compromise joint integrity.

This insert is suited for precision mechanical assemblies where UNF fine-thread engagement is required and vibration or dynamic loading is a concern. Common applications include aerospace structures, industrial machinery, hydraulic component housings, and electrical enclosures where stainless fastener compatibility and corrosion resistance are priorities. The tanged design allows installation with a standard HELI-COIL installation tool; the tang is removed after installation using a notch-break tool. The 2D length provides balanced thread engagement depth for most steel and aluminum parent-material applications.

Key Features

• Grade 304 stainless steel construction resists corrosion and galling in harsh environments
• 10-32 UNF thread profile provides fine-thread engagement for high-load applications
• 2D length-to-diameter ratio at 0.38 inches OAL suits standard thread repair depth requirements
• Tanged design enables controlled installation with a compatible HELI-COIL installation tool
• Maximum locking torque of 13 inch-pounds with a minimum breakaway torque of 2.00 oz-in
• 9-1/2 free coils deliver consistent thread engagement across the full insert length

Compatibility

Designed for use in parent material threads prepared with the corresponding HELI-COIL 10-32 UNF tap and installation tool set for 2D inserts. Accepts standard 10-32 UNF male fasteners.

Installation Notes

Installation requires the parent material to be tapped with the correct HELI-COIL-specified tap for 10-32 UNF inserts prior to driving the insert. Use the designated HELI-COIL installation mandrel or driver to thread the insert flush to slightly below the surface of the parent material. After seating, remove the drive tang using the appropriate tang-break tool; retain or discard the tang per job-site procedure. Always wear eye protection during tang removal.