Heli-coil 5402-4 Thread Repair Kit 1/4-28 Unf

Product Description

The HELI-COIL 5402-4 is a complete thread repair kit designed to restore damaged or stripped 1/4-28 UNF internal threads to full load-bearing strength. The kit centers on helically wound wire thread inserts that, once installed, create a durable threaded surface in the parent material. Insert lengths range from 0.25 inches to 0.5 inches, giving technicians flexibility for shallow and deeper thread repairs in the same bore. This kit is used across mechanical, HVAC, plumbing, and electrical service work wherever a stripped threaded hole must be brought back to spec without replacing the entire component.

This kit is suited for both shop and field repairs on 1/4-28 UNF threaded holes in metal components. It is commonly used by HVAC technicians, pipefitters, electricians, and general maintenance mechanics on equipment housings, control panels, valve bodies, and structural fastener locations. The 36-insert count makes it a practical choice for recurring repair work rather than single-use jobs. Each kit includes everything needed to complete the repair without sourcing additional tooling separately.

Key Features

• Complete kit: includes drill, tap, installation tool, tang removal tool, and 36 inserts
• Thread size 1/4-28 UNF for fine-thread repair applications
• Three insert lengths available: 0.25 inches, 0.375 inches, and 0.5 inches - 12 inserts per length
• Tang removal tool size 3/16 included for clean post-installation breakoff
• Installation tool part number 2299-4 and tap part number 4FPB included in kit
• Insert package part number R1191-4 for reorder reference

Compatibility

Designed for use in any parent material threaded to 1/4-28 UNF specification. Suitable for repair of stripped threads in metal housings, fastener bores, and tapped holes conforming to UNF fine-thread standards.

Installation Notes

Thread repair inserts of this type are installed by licensed mechanics, HVAC technicians, or qualified maintenance personnel following the drill-tap-install sequence. Power down or de-energize any equipment before beginning thread repair work near electrical or control components. Use the included drill and tap to prepare the bore to the correct diameter before driving the insert with the provided installation tool. Remove the tang with the included 3/16 tang removal tool after the insert is fully seated.