Heli-coil 1185-04CN168S Free Running Insert 4-40 Stainless

Product Description

The HELI-COIL 1185-04CN168S is a tanged, free-running wire thread insert designed to create durable, wear-resistant internal threads in tapped holes. Built from 304 stainless steel, this coiled insert installs into a pre-tapped Heli-Coil STI thread and provides a standard 4-40 UNC mating thread once seated. The tanged design allows installation with a standard tang-break tool. At 0.168 inches overall length with a 1-1/2D length-to-diameter ratio and 4-3/4 free coils, this insert restores or reinforces thread integrity in stripped, soft, or high-cycle fastening applications. Licensed trades and precision fabricators rely on these inserts for machine screws in aluminum, cast iron, and other base materials where thread stripping is a concern.

Free-running inserts of this type are used across mechanical, electrical, HVAC, and industrial assembly applications wherever a 4-40 UNC threaded connection requires reinforcement or repair. The 1185-04CN168S is appropriate for both OEM production environments and field repair scenarios. This package contains 1000 inserts, making it well-suited for production-volume use. Applications include control panels, equipment housings, small motor assemblies, and any assembly where a lightweight base material must carry a machine screw thread reliably.

Key Features

• 4-40 UNC thread size, compatible with standard 4-40 machine screws
• 304 stainless steel construction for corrosion resistance and hardness
• Tanged design for positive engagement during installation with a tang-break tool
• 0.168 inches overall length at a 1-1/2D length-to-diameter ratio
• 4-3/4 free coils for consistent thread engagement across the full insert length
• Bulk pack of 1000 inserts for production or high-volume service use

Compatibility

Designed for use in Heli-Coil STI pre-tapped holes sized for a 4-40 UNC free-running insert with a 1-1/2D length-to-diameter ratio. Requires the appropriate Heli-Coil STI tap and installation tool for proper fitment.

Installation Notes

Installation requires a correctly sized Heli-Coil STI tap to prepare the receiving hole prior to insert placement. Use the matching Heli-Coil installation tool to drive the insert to the correct depth without over-torquing. After installation, break the driving tang using a tang-break tool or punch; remove tang fragments from blind holes before assembly. Follow the fastener and equipment manufacturer guidelines for pre-tap drill sizing and insert depth requirements.