Heli-coil A3591-3CN190 Screw-locking Insert 10-32 Unf

Product Description

The HELI-COIL A3591-3CN190 is a tangless screw-locking wire thread insert designed to create a secure, vibration-resistant threaded repair or reinforcement in parent materials that cannot reliably hold a fastener on their own. Manufactured from Grade 304 stainless steel with a bright finish, this insert accepts a 10-32 UNF screw thread and installs to a 1D length-to-diameter ratio with an overall installed length of 0.190 inches. The coil design provides a maximum locking torque of 13 inch-pounds, making it suitable for assemblies subject to dynamic loads or thermal cycling. The tangless design eliminates the need to break off a driving tang after installation, reducing debris risk in critical assemblies.

This insert is used in light-gauge metal, aluminum, magnesium, plastic, and other low-strength parent materials where standard threads would strip or fail under repeated fastening cycles. Typical applications include equipment housings, control panels, compressor bodies, motor end bells, and structural brackets found in HVAC, refrigeration, electrical, and mechanical service work. It is installed by licensed technicians and maintenance professionals performing thread repair or original equipment assembly. The single-insert packaging supports field repair scenarios where only one or a few holes require service.

Key Features

• Tangless design eliminates post-install tang removal and keeps debris out of finished assemblies
• Grade 304 stainless steel construction resists corrosion in wet or chemically active environments
• 10-32 UNF thread standard for fine-pitch fastener compatibility
• Maximum locking torque of 13 inch-pounds provides reliable vibration resistance
• Minimum outside diameter of 0.236 inches and maximum outside diameter of 0.256 inches for precise hole sizing
• 4-1/8 free coils deliver consistent thread engagement across the insert length

Compatibility

Designed as an OEM-style thread insert for applications requiring a 10-32 UNF screw-locking insert with a 1D length-to-diameter ratio in any parent material accepting a corresponding HELI-COIL tang-drive or tangless installation tool.

Installation Notes

Installation requires the correct HELI-COIL tangless installation tool sized for 10-32 UNF inserts; do not attempt installation with standard screwdrivers or improvised tools, as this will damage the coil. The parent material must first be drilled to the HELI-COIL specified tap drill size and tapped with a HELI-COIL STI tap before the insert is driven. Power down or de-energize any equipment before performing thread repair work on electrical or HVAC components. Verify the installed insert is flush with or slightly below the parent material surface before torquing the mating fastener.