Heli-coil A1185-04CN168 Free Running Insert 4-40 Unc

Product Description

The HELI-COIL A1185-04CN168 is a tanged, free running wire thread insert designed to create strong, wear-resistant internal threads in materials that cannot hold a standard thread on their own. Built from 304 stainless steel with a bright, uncoated finish, this insert measures 0.168 inches in overall length and accepts a 4-40 UNC thread. The coil design distributes load across multiple thread engagements, extending the service life of tapped holes in aluminum, magnesium, cast iron, and similar materials. Licensed tradespeople and maintenance technicians working on electrical enclosures, HVAC components, and mechanical assemblies use these inserts for thread repair and new-thread installation.

This insert is suited for applications requiring a 1-1/2D length-to-diameter ratio in 4-40 UNC threaded holes. Its compact 0.168-inch length fits tight spaces common in control boards, motor housings, and light equipment frames. The tanged design allows installation with a standard Heli-Coil driver tool, and the tang is removed after seating. With 4-3/4 free coils, it provides reliable thread engagement for fasteners in both new construction and thread-repair scenarios across residential and light commercial trade work.

Key Features

• 4-40 UNC thread size for compatibility with standard inch-series fasteners
• 0.168-inch overall length at a 1-1/2D length-to-diameter ratio
• 304 stainless steel construction for corrosion resistance in demanding environments
• Tanged design for positive installation with a Heli-Coil driver tool
• 4-3/4 free coils provide distributed thread engagement and load sharing
• Bright, uncoated finish - no additional treatment needed for most interior applications

Compatibility

Designed as an OEM-style thread insert for 4-40 UNC tapped holes in aluminum, magnesium, thermoplastics, and other materials requiring thread reinforcement or repair.

Installation Notes

Installation requires a properly sized Heli-Coil tap to prepare the host material before driving the insert. Power down any assembly completely before thread repair on energized components. After seating the insert flush with or slightly below the surface, remove the tang using a tang break-off tool or a punch placed at the notch - never leave the tang in a blind hole without confirming full removal. Follow applicable mechanical codes and the fastener manufacturer torque guidelines for the specific base material.