Heli-coil A3585-4CN250 Screw-locking Insert 1/4-20 Unc

Product Description

The HELI-COIL A3585-4CN250 is a tangless screw-locking helical thread insert designed to create and reinforce durable internal threads in a host material while providing positive locking performance. Manufactured from Grade 304 stainless steel with a bright finish, this insert measures 0.25 inches in overall length at a 1D length-to-diameter ratio for 1/4-20 UNC threading applications. It delivers a maximum locking torque of 30 in/lb and a minimum breakaway torque of 4.50 in/lb, making it well suited for joints that must resist vibration loosening. Machinists, maintenance technicians, and assembly professionals install this insert to restore stripped threads or establish precision internal threads in new assemblies.

This insert is used in industrial, aerospace, automotive, and general mechanical assembly applications where 1/4-20 UNC threads are required in materials prone to thread wear or stripping. The tangless design eliminates the need for tang removal after installation, streamlining the installation process in both production and field-repair environments. Its stainless steel construction provides corrosion resistance, making it appropriate for assemblies exposed to moisture or moderate chemical environments.

Key Features

• Tangless design eliminates post-installation tang removal for faster, cleaner assembly
• Grade 304 stainless steel construction provides corrosion resistance and durability
• Maximum locking torque of 30 in/lb resists vibration-induced thread loosening
• Minimum breakaway torque of 4.50 in/lb ensures reliable locking under service loads
• Bright finish with 3 to 3/8 free coils for consistent thread engagement
• Outside diameter range of 0.31 to 0.33 inches suits standard heli-coil tapped holes

Compatibility

Designed as an OEM-style thread repair and reinforcement insert for host materials tapped to accept 1/4-20 UNC helical insert specifications.

Installation Notes

Installation requires a properly sized heli-coil tap and the appropriate tangless installation tool for the 1/4-20 UNC insert series. The host material bore must be drilled and tapped to the correct insert tap drill size before the insert is driven in. Power down or de-energize any associated equipment before servicing threaded connections in live assemblies. Do not reuse an insert once it has been removed from a host material.