Heli-coil 1185-4CN250S 1/4-20 Thread Insert Stainless 1000

Product Description

The HELI-COIL 1185-4CN250S is a free-running helical wire thread insert designed to create strong, wear-resistant internal threads in softer or damaged base materials. Manufactured from 304 stainless steel, this tanged insert accepts a 1/4-20 UNC thread and measures 0.25 inches overall length, corresponding to a 1D length-to-diameter ratio. The insert includes 3-3/8 free coils and is installed using a standard HELI-COIL installation mandrel after the parent material has been drilled and tapped to the appropriate insert tap size. This package contains 1000 inserts, making it suitable for production or fleet maintenance operations.

Free-running inserts of this type are used in a wide range of repair and manufacturing applications where a 1/4-20 UNC thread must be established or restored in aluminum, magnesium, cast iron, plastics, or other materials prone to thread stripping. Common install scenarios include HVAC equipment housings, electrical enclosures, pump bodies, and general mechanical assemblies where thread integrity is critical. The 304 stainless steel construction resists corrosion and is compatible with most operating environments encountered in light industrial and field-service work.

Key Features

• 1/4-20 UNC thread size with 0.25-inch overall insert length (1D ratio)
• Tanged design for controlled installation using a standard installation tool; tang is removed after seating
• 304 stainless steel construction for corrosion resistance and durability
• 3-3/8 free coils provide full thread engagement in a compact insert length
• Bulk package of 1000 inserts supports production-volume or high-frequency repair work

Compatibility

Designed as an OEM-style thread repair and insert solution for any application requiring a 1/4-20 UNC internal thread; requires use of the corresponding HELI-COIL STI tap and installation tool for proper fitment.

Installation Notes

Thread inserts are installed by machining or maintenance technicians familiar with helical insert procedures. Power down and de-energize or depressurize the host assembly before drilling or tapping operations begin. Use the correct STI tap size for 1/4-20 inserts and the matching installation mandrel to drive the insert to the proper depth. After installation, remove the tang with a tang break-off tool; inspect the completed thread with a standard 1/4-20 go/no-go gauge before returning the assembly to service.