Heli-coil AT3585-02C129 Screw-locking Insert 2-56 Unc

Product Description

The HELI-COIL AT3585-02C129 is a tangless screw-locking helical coil insert designed to create a durable, vibration-resistant internal thread in tapped holes. Manufactured from grade 304 stainless steel with a bright finish, this insert installs into a prepared 2-56 UNC tapped hole to lock threaded fasteners in place under dynamic load or vibration. At 0.129 inches overall length and a 1-1/2D length-to-diameter ratio, it is sized for compact assemblies where space is limited. The tangless design eliminates the need to break off an installation tang after seating, saving installation time and preventing loose metal debris inside assemblies. Licensed trade technicians and precision assembly mechanics install this type of insert in aerospace, industrial, and mechanical applications.

This insert is suited for use in metal assemblies where a 2-56 UNC thread needs repair or reinforcement, or where a softer base material requires a stronger mating thread. The 1-1/2D length provides a balance between pullout strength and overall hole depth. With a maximum locking torque of 20 oz-in and a minimum breakaway torque of 3 oz-in, it maintains fastener position without permanently locking the bolt in place, allowing for future serviceability. Typical applications include precision instrument housings, electronic enclosures, and light mechanical assemblies where stainless steel corrosion resistance is required.

Key Features

• Tangless design eliminates post-installation tang removal and reduces debris risk
• Grade 304 stainless steel construction provides corrosion resistance in demanding environments
• Maximum locking torque of 20 oz-in keeps fasteners secure under vibration
• Minimum breakaway torque of 3 oz-in allows for future fastener removal and reinstallation
• Bright finish with 5-1/4 free coils for consistent thread engagement
• Outside diameter range of 0.110 to 0.119 inches for standard 2-56 UNC insert taps

Compatibility

Designed as an OEM-style screw-locking insert for 2-56 UNC tapped holes requiring a 1-1/2D helical coil thread insert. Use with the appropriate HELI-COIL installation tool for tangless inserts sized to the 2-56 thread series.

Installation Notes

Installation requires a correctly sized 2-56 UNC STI tap to prepare the receiving hole and a tangless insert installation tool matched to this thread size. Power down or de-energize any assembly before beginning thread repair work to prevent inadvertent contact with live circuits or moving components. Do not use standard tanged installation tools with tangless inserts, as this can damage the coil or the receiving thread. Follow the assembly manufacturer guidelines and any applicable industry standards for thread insert repair procedures.