Heli-coil T3585-02C129S 2-56 Unc Screw-locking Insert 1000-pack

Product Description

The HELI-COIL T3585-02C129S is a tangless, screw-locking wire thread insert designed to create a strong, vibration-resistant internal thread in a parent material. It accepts a 2-56 UNC screw thread and measures 0.129 inches overall length at a 1-1/2D length-to-diameter ratio. Manufactured from Grade 304 stainless steel, it resists corrosion and maintains thread integrity under repeated assembly and disassembly cycles. The screw-locking design uses a deformed coil section to generate prevailing torque, preventing fastener back-out under vibration. Installation and removal do not require a tang-break step, streamlining production and service workflows. This package contains 1000 inserts.

This insert is used in applications where a fine, reliable internal thread must be installed in soft or worn parent materials including aluminum, magnesium, cast iron, plastics, and composites. Common application areas include aerospace assemblies, precision instruments, electronic enclosures, and light mechanical equipment where 2-56 UNC fasteners are standard. The tangless design suits both automated insertion equipment and hand installation tooling, making it appropriate for production-line use and field repair work. A licensed mechanic, assembly technician, or experienced maintenance professional typically installs this part.

Key Features

• Tangless design eliminates tang-break step during installation and removal
• Screw-locking coil section delivers a maximum locking torque of 20 oz-in
• Minimum break-away torque of 3.00 oz-in maintains prevailing torque after repeated cycling
• Grade 304 stainless steel construction resists corrosion in wet or chemically active environments
• 5-1/4 free coils with outside diameter range of 0.110 to 0.119 inches for controlled installation fit
• Pack of 1000 inserts supports production-volume requirements

Compatibility

Designed as an OEM-style replacement or production insert for any application requiring a 2-56 UNC screw-locking thread insert at a 1-1/2D length-to-diameter ratio.

Installation Notes

Installation requires the correct HELI-COIL installation tool sized for 2-56 UNC tangless inserts. The parent material must be drilled and tapped to the manufacturer-specified STI (Screw Thread Insert) tap dimensions before insertion. Power down or de-energize any assembly before reworking threaded holes in energized equipment. Do not attempt to install thread inserts in an undersized or improperly tapped hole, as this can damage the insert coil or the parent bore.