Heli-coil A3591-3CNPF285 10-32 Unf Locking Insert

Product Description

The HELI-COIL A3591-3CNPF285 is a tangless screw-locking helical coil insert designed to create strong, vibration-resistant threads in parent material. It installs without a tang-break step, eliminating the risk of tang fragments in blind holes or precision assemblies. Sized for 10-32 UNF threads with a 1-1/2D length-to-diameter ratio and an overall length of 0.285 inches, this insert is manufactured from Grade 304 stainless steel with a primer-free finish. It delivers a maximum locking torque of 13 inch-pounds and a minimum break-away torque of 2.00 ounce-inches. Machinists, maintenance technicians, and assembly professionals install this type of insert to restore or reinforce threaded holes in metal components.

This insert is suited for applications requiring reliable thread locking in stainless-compatible assemblies, including aerospace, industrial machinery, electronics enclosures, and precision mechanical assemblies. The tangless design makes it well-suited for automated installation as well as manual installation in confined spaces or blind holes where tang removal would be difficult. The 304 stainless steel construction provides corrosion resistance in wet or chemically exposed environments. Sold individually; a minimum order quantity of 10 units applies.

Key Features

• Tangless design eliminates tang-break step and prevents fragment contamination in blind holes
• Grade 304 stainless steel construction for corrosion resistance
• 10-32 UNF thread standard, 1-1/2D length-to-diameter ratio
• Maximum locking torque of 13 inch-pounds for vibration-resistant thread retention
• Minimum outside diameter of 0.236 inches, maximum outside diameter of 0.256 inches
• Primer-free finish for clean installation without surface prep requirements

Compatibility

Designed as a replacement or new-installation locking insert for any application requiring a 10-32 UNF helical coil thread insert with a 1-1/2D engagement length.

Installation Notes

Installation requires a properly sized Heli-Coil tap to prepare the parent hole before insert placement. Use the appropriate tangless installation tool to drive the insert to the correct depth without overtightening. Always ensure the parent material is securely fixtured and power is removed from any assembly before reworking threaded holes in electrical or mechanical equipment. Follow the fastener manufacturer torque specifications for the mating screw to avoid overloading the insert after installation.