Heli-coil A1185-4EN375 Free Running Insert 1/4-20 Unc

Product Description

The HELI-COIL A1185-4EN375 is a free running helical wire thread insert designed to restore or reinforce threaded holes in metal components. It installs into a pre-drilled and tapped host material, creating a durable internal thread that accepts standard 1/4-20 UNC fasteners. Constructed from 18-8 stainless steel, it offers corrosion resistance suitable for demanding service environments. The insert measures 0.375 inches overall length, which corresponds to a 1-1/2D length-to-diameter ratio. A tanged design aids installation using a standard HELI-COIL insertion tool. Typically installed by machinists, maintenance technicians, or field service professionals during thread repair or new-part fabrication work.

This insert is suited for applications requiring reliable thread repair or thread reinforcement in aluminum, cast iron, steel, or other base materials. The 1/4-20 UNC thread is a common fastener size across HVAC equipment panels, electrical enclosures, pump housings, and general mechanical assemblies. The 5-3/4 free coils provide consistent thread engagement across the full insert length. MOQ is 10 units; each package contains 1 insert.

Key Features

• 1/4-20 UNC thread size for compatibility with standard inch-series fasteners
• 0.375 inches overall length with 1-1/2D length-to-diameter ratio
• 18-8 stainless steel construction for corrosion resistance
• Tanged design for use with standard HELI-COIL insertion tooling
• 5-3/4 free coils for full thread engagement across insert length

Compatibility

Designed as a standard free running helical thread insert for 1/4-20 UNC tapped holes in metallic base materials requiring thread repair or reinforcement.

Installation Notes

Installation requires a properly sized HELI-COIL tap and a compatible insertion tool; refer to the manufacturer tool chart for the correct tap drill size for 1/4-20 UNC inserts. Power down any equipment and remove the component from service before performing thread repair. After driving the insert to the correct depth, break off the installation tang using a tang break-off tool or needle-nose pliers. Follow applicable shop safety procedures when working with cutting tools and metal chips.