Heli-coil A4184-8CNW120 Screw-locking Insert M8 X 1.25

Product Description

The HELI-COIL A4184-8CNW120 is a tangless screw-locking helical wire insert designed to create or restore strong, vibration-resistant threads in parent materials. Built from Grade 304 stainless steel with a dry film lubricant finish, this insert accepts an M8 x 1.25 metric coarse thread and provides a 1-1/2D length-to-diameter ratio for reliable thread engagement. At 12 mm overall length, the insert delivers a maximum locking torque of 6.00 N/m and a minimum break-away torque of 0.80 N/m, keeping fasteners secure under dynamic loads. Mechanical and maintenance professionals specify this insert when thread repair or thread reinforcement is required in metal assemblies.

This insert is suited for industrial, automotive, aerospace-adjacent, and general mechanical applications where metric coarse thread integrity is critical. The tangless design eliminates the need to remove a tang after installation, reducing installation steps and the risk of loose debris inside blind holes. With 7-3/8 free coils, the insert distributes clamp load across multiple thread engagements, making it appropriate for both original equipment manufacture and field thread repair work.

Key Features

• Tangless design eliminates post-installation tang removal and reduces debris risk in blind holes
• Grade 304 stainless steel construction resists corrosion in harsh or wet environments
• Dry film lubricant finish reduces installation torque and protects threads during assembly
• Maximum locking torque of 6.00 N/m keeps fasteners secure under vibration and dynamic loading
• Minimum outside diameter of 9.80 mm and maximum of 10.35 mm for consistent fit in prepared bores
• 1-1/2D length-to-diameter ratio provides full thread engagement in standard parent material depths

Compatibility

Designed for use in tapped parent material holes prepared for M8 x 1.25 metric coarse helical insert installation. Requires a HELI-COIL-specified tap and tangless installation tool sized for M8 x 1.25 inserts.

Installation Notes

Installation must be performed using a tap and installation tool matched to the M8 x 1.25 tangless insert specification. Prepare the parent material hole to the correct tap drill diameter and thread the bore before driving the insert. Power down any equipment and relieve system pressure before performing thread repair on in-service components. Tangless inserts require a dedicated tangless driver and do not use standard tang-style installation tooling.