Heli-coil A3585-4CN500 Screw-locking Insert 1/4-20 Unc

Product Description

The HELI-COIL A3585-4CN500 is a tangless screw-locking helical coil insert designed to create strong, vibration-resistant threaded holes in parent materials. The insert accepts 1/4-20 UNC fasteners and delivers a 2D length-to-diameter ratio with an overall length of 0.5 inches. Manufactured from Grade 304 stainless steel with a bright finish, it resists corrosion in demanding service environments. A maximum locking torque of 30 in/lb and a minimum breakaway torque of 4.50 in/lb ensure fasteners stay secured under load. Machinists, maintenance technicians, and MRO professionals install these inserts to repair damaged threads or reinforce threads in softer base materials.

This insert is suited for applications in industrial, commercial, and light mechanical assembly where 1/4-20 UNC threaded connections must hold against vibration or repeated fastener cycling. The tangless design eliminates the need for tang removal after installation, which simplifies the process and reduces debris in blind-hole applications. It is appropriate for use in aluminum, cast iron, magnesium, plastics, and other materials where thread strength needs to meet or exceed the original specification.

Key Features

• Tangless design eliminates post-installation tang removal and reduces installation steps
• Grade 304 stainless steel construction provides corrosion resistance in wet or chemically exposed environments
• 1/4-20 UNC thread size with 2D length-to-diameter ratio for balanced thread engagement
• Maximum locking torque of 30 in/lb keeps fasteners secure under vibration
• Minimum outside diameter of 0.31 inches and maximum outside diameter of 0.33 inches for precise fit in prepared holes
• Bright finish for easy visual inspection during installation

Compatibility

Designed as an OEM-style replacement or new-installation insert for applications requiring 1/4-20 UNC screw-locking thread repair or thread reinforcement in a range of parent materials.

Installation Notes

Installation requires a properly sized HELI-COIL tap to prepare the parent hole to the correct oversize dimension before the insert is driven in. Use the appropriate tangless installation tool for this insert series to avoid damage to the coil. Power down or de-energize any equipment before performing thread repair on in-service components. Follow facility-specific torque and assembly procedures when setting final fastener torque after insert installation.