Heli-coil A1191-3CNPF285 Free Running Insert 10-32 0.285in

Product Description

The HELI-COIL A1191-3CNPF285 is a free running wire thread insert designed to restore or reinforce 10-32 UNF threads in metallic and non-metallic parent materials. Manufactured from 304 stainless steel with a primer-free finish, this tanged insert measures 0.285 inches overall length and carries a 1-1/2D length-to-diameter ratio. It installs into a pre-tapped STI (Screw Thread Insert) hole using a standard HELI-COIL installation tool, expanding radially to lock into the parent material and provide a wear-resistant, corrosion-resistant thread form. Licensed mechanical and maintenance technicians use these inserts during equipment repair and assembly work.

This insert is suited for applications requiring a durable 10-32 UNF threaded anchor point in aluminum, cast iron, plastics, and other materials prone to thread stripping or wear. Typical install scenarios include equipment housings, HVAC component brackets, electrical enclosures, and precision assemblies where retaining original thread integrity is critical. The tanged design allows for secure seating during installation, with the tang removed after insertion using a break-off tool.

Key Features

• 10-32 UNF thread size for compatibility with standard unified fine-thread fasteners
• 304 stainless steel construction for corrosion resistance in demanding environments
• Primer-free finish - ready to install without additional surface preparation
• Tanged design for positive engagement during installation
• 0.285 inches OAL with 1-1/2D length-to-diameter ratio for solid thread engagement
• 6-7/8 free coils provide consistent thread load distribution

Compatibility

Designed as an OEM-style thread repair and reinforcement insert for parent materials tapped to HELI-COIL STI specifications in 10-32 UNF thread form.

Installation Notes

Installation requires a pre-tapped STI hole and a manufacturer-specified HELI-COIL installation tool - standard thread taps are not compatible with STI dimensions. Power down or de-energize any equipment before accessing threaded bores in live assemblies. After the insert is fully seated, use a HELI-COIL tang break-off tool to remove the drive tang; failure to remove the tang may interfere with fastener seating. This work is typically performed by mechanical technicians, field service engineers, or maintenance professionals.