Heli-coil A3585-5CNW312 Screw-locking Insert 5/16-18 Unc

Product Description

The HELI-COIL A3585-5CNW312 is a tangless screw-locking helical wire insert designed to create a durable, vibration-resistant threaded hole in parent materials that require reinforced fastening. Manufactured from Grade 304 stainless steel with a dry film lubricant finish, it installs into a prepared tapped hole to restore or reinforce internal threads to a 5/16-18 UNC specification. The 1D length-to-diameter ratio gives an overall insert length of 0.312 inches, making it well suited for applications where thread engagement depth is limited. Licensed mechanics, maintenance technicians, and field service pros use this insert when stripped or damaged threads need a permanent, corrosion-resistant fix.

This insert is appropriate for use in aerospace, industrial, and heavy-equipment maintenance environments where thread integrity under load and vibration is critical. The screw-locking feature introduces a prevailing torque that resists fastener back-out under dynamic loads. The tangless design eliminates the tang-removal step required with standard helical inserts, reducing installation time and the risk of tang debris inside a blind hole. It is sold as a single insert per package with a minimum order quantity of 10 units.

Key Features

• Grade 304 stainless steel construction resists corrosion in harsh or wet service environments
• Tangless design removes the need for tang extraction after installation, reducing debris risk in blind holes
• Screw-locking coil provides prevailing torque with a maximum locking torque of 60 inch-pounds and a minimum breakaway torque of 7.50 inch-pounds
• Dry film lubricant finish reduces installation friction and supports consistent torque values during fastener installation
• 4 free coils and a 1D length-to-diameter ratio suit applications with limited thread engagement depth
• 5/16-18 UNC thread standard fits widely used inch-series fasteners across industrial and mechanical assemblies

Compatibility

Designed as an OEM-style thread repair and reinforcement insert for parent material tapped to accept a 5/16-18 UNC helical insert. Outside diameter ranges from a minimum of 0.380 inches to a maximum of 0.400 inches.

Installation Notes

Installation requires a properly prepared tapped hole drilled and tapped to the appropriate HELI-COIL insert tap specification for 5/16-18 UNC. A tangless insert installation tool compatible with this thread size and insert series should be used. Power down or de-energize any equipment before accessing fastener locations in live assemblies. Do not use standard tang-style installation tools with tangless inserts, as the drive geometry is not interchangeable.