Heli-coil A1185-4CN250 1/4-20 Free Running Insert

Product Description

The HELI-COIL A1185-4CN250 is a free running helical wire thread insert designed to create strong, wear-resistant threads in parent materials that may be soft, damaged, or prone to thread stripping. The insert measures 0.25 inches in overall length with a 1/4-20 UNC thread size and a 1D length-to-diameter ratio. Constructed from 304 stainless steel with a bright, uncoated finish, it provides corrosion resistance in demanding service environments. The tanged design allows installation with a standard HELI-COIL installation tool. This insert is used by maintenance technicians, machinists, and field service professionals across industrial, mechanical, and HVAC equipment repair applications.

This insert is suited for restoring stripped or damaged 1/4-20 UNC threads in metal housings, brackets, and assemblies. It is commonly used in equipment repair scenarios where parent-material threads have failed due to overtorque, corrosion, or repeated fastener removal. The 1D length matches the 0.25-inch overall insert length for a compact fitment profile. Each unit is sold individually, with a minimum order quantity of 10 pieces per order.

Key Features

• 1/4-20 UNC thread size for broad fastener compatibility
• 0.25-inch overall length with 1D length-to-diameter ratio for compact installations
• 304 stainless steel construction for corrosion resistance
• Tanged design compatible with standard HELI-COIL installation tooling
• Bright, uncoated finish - no coating interference with thread tolerances
• 3-3/8 free coils for consistent thread engagement

Compatibility

Designed as a standard-duty free running insert for any parent material tapped to accept a 1/4-20 UNC HELI-COIL insert of 1D length, including aluminum, cast iron, magnesium, and steel housings commonly found in mechanical and HVAC equipment assemblies.

Installation Notes

Installation requires a correctly sized HELI-COIL tap and a matching installation tool for 1/4-20 inserts. The parent material bore must be drilled and tapped to the HELI-COIL insert tap drill size before installation. After driving the insert to the correct depth, the installation tang must be broken off using a tang break-off tool. Always de-energize or shut down equipment before performing thread repair work on live assemblies.