Heli-coil T1185-4C375S Free Running Insert 1/4-20 Unc

Product Description

The HELI-COIL T1185-4C375S is a tangless, free-running helical wire thread insert designed to create strong, wear-resistant internal threads in drilled and tapped holes. Made from 304 stainless steel, this insert accepts a 1/4-20 UNC thread and measures 0.375 inches overall length, corresponding to a 1-1/2D length-to-diameter ratio. The tangless design eliminates the need for a separate tang removal step after installation, reducing assembly time and eliminating the risk of broken tangs contaminating the workpiece. Machinists, maintenance technicians, and MRO professionals install these inserts to repair stripped threads or to build up thread strength in softer base materials.

This insert is suited for applications in light manufacturing, equipment maintenance, and thread repair across metalworking and industrial assembly environments. It performs in ferrous and non-ferrous base materials where a corrosion-resistant 304 stainless steel thread form is specified. With 5-3/4 free coils and a 0.375-inch body length, it provides reliable thread engagement appropriate for general fastening duties in both production and field repair scenarios. Installers typically use a dedicated HELI-COIL installation tool matched to the 1/4-20 thread size.

Key Features

• Tangless design eliminates post-installation tang removal and reduces contamination risk
• 304 stainless steel construction for corrosion resistance in demanding environments
• 1/4-20 UNC thread size with 0.375-inch overall length and 1-1/2D length-to-diameter ratio
• 5-3/4 free coils for consistent thread engagement across the insert body
• Sold in a quantity of 1000 inserts per package, suitable for production and MRO stocking

Compatibility

Designed as an OEM-style free-running thread insert for use in tapped holes requiring 1/4-20 UNC internal threads in standard helical insert applications.

Installation Notes

Installation requires a dedicated helical insert installation tool matched to the 1/4-20 thread size and a properly sized STI (Screw Thread Insert) tap to prepare the receiving hole. Power down or de-energize any equipment before performing thread repair on live assemblies. The tangless design does not require a tang break-off tool, but the hole must be tapped to the correct STI tap drill size and depth before inserting. Follow applicable facility safety and torque specifications for the final fastener as determined by the engineer of record.