Heli-coil A4184-4CN040 Screw-locking Insert M4 X 0.70 1D

Product Description

The HELI-COIL A4184-4CN040 is a tangless screw-locking helical wire insert designed to create or restore strong, vibration-resistant threads in tapped parent material. Manufactured from Grade 304 stainless steel with a bright finish, this insert accepts an M4 x 0.70 metric coarse thread and provides a 1D length-to-diameter ratio with an overall insert length of 4.00 mm. The coiled design exerts radial pressure against both the installed bolt and the parent bore, generating a locking effect without secondary hardware. Maintenance technicians, aerospace assemblers, and precision equipment technicians install these inserts wherever thread failure or pull-out resistance is a concern.

This insert is suited for applications in stainless-compatible environments where corrosion resistance and sustained clamp load matter. Typical installation scenarios include light industrial equipment, instrumentation housings, medical device assemblies, and structural components subject to repeated fastener removal. The tangless design eliminates the need for a tang break-off step after installation, reducing debris risk inside closed assemblies. The 1D length makes it appropriate for thin-wall or space-constrained boss geometries where longer inserts are not practical.

Key Features

• Tangless design eliminates post-installation tang removal and reduces contamination risk in closed assemblies
• Grade 304 stainless steel construction provides corrosion resistance in wet or chemically active environments
• M4 x 0.70 metric coarse thread profile for broad fastener compatibility
• 1D length-to-diameter ratio suits thin-wall and space-constrained boss applications
• Maximum locking torque of 0.90 N/m with a minimum break-away torque of 0.16 N/m for controlled vibration resistance
• Bright finish for consistent appearance and dimensional inspection

Compatibility

Designed as an OEM-style replacement or new-installation insert for any parent material tapped to accept an M4 x 0.70 metric coarse helical insert, using the corresponding HELI-COIL or compatible tangless installation tool and drill-tap specification.

Installation Notes

A licensed machinist or qualified assembly technician should install this insert using the correct tangless installation tool matched to the M4 x 0.70 insert series. The parent hole must be drilled and tapped to the insert manufacturer's specified STI (Screw Thread Insert) tap size before installation. Ensure the parent bore is clean and free of chips before driving the insert. No tang removal step is required with the tangless design, but verify insert seating depth meets the engineering specification for the assembly.