Heli-coil T3585-04C224S 4-40 Unc 2D Locking Insert SS304

Product Description

The HELI-COIL T3585-04C224S is a screw-locking helical wire thread insert designed to create a secure, vibration-resistant internal thread in tapped holes. Manufactured from Grade 304 stainless steel, this tanged insert installs into a pre-tapped Heli-Coil STI hole to deliver a 4-40 UNC female thread with a 2D length-to-diameter ratio and an overall length of 0.224 inches. The locking feature is built into a series of non-circular coils that grip the mating fastener and resist self-loosening under dynamic loads. Machinists, MRO technicians, and assembly professionals use this insert in precision thread repair and original equipment assembly work.

This insert is suited for applications where thread integrity and vibration resistance are critical, including aerospace assemblies, electronics enclosures, instrumentation, and light mechanical assemblies. The Grade 304 stainless steel construction resists corrosion in moderate environments. The 2D configuration keeps the installed profile compact while delivering reliable locking performance. This listing includes 1000 inserts per package, making it appropriate for production-run or bench-stock use rather than single-repair service calls.

Key Features

• Screw-locking design resists vibration-induced loosening without adhesives or thread-locking compounds
• Grade 304 stainless steel construction provides corrosion resistance in moderate-duty environments
• 4-40 UNC thread standard for small-fastener applications in precision assemblies
• Overall length of 0.224 inches with a 2D length-to-diameter ratio for compact installation depth
• Maximum locking torque of 48 oz-in with a minimum breakaway torque of 10 oz-in
• Tanged installation style for use with standard Heli-Coil tang break-off tools
• Pack of 1000 inserts supports production-volume or high-turnover bench stock

Compatibility

Designed for installation into STI-tapped holes prepared for 4-40 UNC Heli-Coil style inserts. Requires the appropriate Heli-Coil STI tap and installation tool for the 4-40 thread size.

Installation Notes

Installation requires a properly prepared STI-tapped hole sized to the insert manufacturer's specification for 4-40 UNC. Use the correct Heli-Coil installation mandrel to wind the insert into the hole without distorting the coils. After installation, break off the tang using an approved tang break-off tool. Always de-energize and lock out any equipment before performing thread repair or insert installation on in-service components.