Heli-coil A1185-05CN250 Free Running Insert 5-40 Unc

Product Description

The HELI-COIL A1185-05CN250 is a free running helical wire threaded insert designed to create strong, wear-resistant internal threads in tapped holes. This insert accepts a 5-40 UNC thread and measures 0.25 inches overall length, placing it in the 2D length-to-diameter ratio category. Constructed from 304 stainless steel with a bright, uncoated finish, it delivers corrosion resistance and dimensional stability in demanding service environments. The tanged design allows for installation with a standard HELI-COIL drive tool, and the tang is removed after installation using a tang break-off tool. Machinists, maintenance technicians, and assembly professionals install these inserts to repair stripped threads or reinforce parent material in aluminum, cast iron, magnesium, and other soft alloys.

This insert is suited for applications requiring a reliable UNC thread repair or thread reinforcement in thin-wall or soft parent materials. Typical use cases include precision equipment assemblies, aerospace ground support fixtures, industrial machinery, and maintenance repair operations where a 5-40 thread form must be restored or strengthened. The 304 stainless steel construction makes it appropriate for environments with exposure to moisture or mild chemical agents. Each insert is sold individually, though a minimum order quantity applies per product listing.

Key Features

• 5-40 UNC thread form for compatibility with standard inch-series fasteners
• 0.25 inches overall length at a 2D length-to-diameter ratio for balanced thread engagement
• 304 stainless steel construction provides corrosion resistance and long-term durability
• Bright, uncoated finish maintains tight dimensional tolerances right out of the package
• Tanged design works with standard HELI-COIL installation and tang break-off tooling
• 7-3/4 free coils for consistent load distribution across the insert length

Compatibility

Designed as an OEM-style thread repair insert for use in any parent material tapped to accept a 5-40 UNC helical insert, including aluminum, cast iron, and magnesium alloys. Requires a matching HELI-COIL STI tap and drive tool sized for the 5-40 series.

Installation Notes

Installation is performed by machinists or maintenance technicians using a properly sized STI tap, an installation mandrel, and a tang break-off tool. De-energize or lock out any equipment before performing thread repair work on installed assemblies. Do not exceed the recommended tap drill size for the parent material, as oversized holes reduce insert retention. Follow the tap manufacturer's feed rate and lubrication guidelines for the specific parent material being drilled and tapped.