Heli-coil 18193-10 Hand Sti Tap 5/8-18 Unf H4

Product Description

The HELI-COIL 18193-10 is a hand STI tap designed to cut threads for Heli-Coil wire thread insert installation. It cuts a 5/8-18 UNF thread to an H4 thread limit with a plug chamfer, making it suitable for through-hole and deep blind-hole applications where gradual thread engagement is required. Constructed from high speed steel with a bright finish, this tap delivers consistent cutting performance in steel, aluminum, and cast iron. Four flutes provide adequate chip clearance for most hand tapping operations. A licensed HVAC tech, mechanic, or machinist installs this tap when repairing stripped or damaged threads in metal components.

This STI tap is used when installing Heli-Coil inserts to restore or reinforce threads in metal parts across HVAC equipment housings, compressor bodies, pump casings, and other mechanical assemblies. It is suited for residential and light commercial maintenance and repair work where thread restoration is performed by hand. The plug chamfer allows the tap to start easily and follow through a pre-drilled hole, making it practical for field and shop use alike.

Key Features

• 5/8-18 UNF thread size cuts threads for standard Heli-Coil wire insert installation
• H4 thread limit provides correct oversize tolerance for insert fit
• Plug chamfer allows gradual thread engagement, suitable for through-holes and deep blind holes
• Four flutes provide chip clearance during hand tapping operations
• High speed steel construction resists wear when cutting ferrous and non-ferrous metals
• Bright finish with no coating for straightforward inspection and re-sharpening

Compatibility

Designed as an STI tap for use with Heli-Coil thread insert systems requiring a 5/8-18 UNF H4 thread preparation in Class 2B fit applications.

Installation Notes

This tap is installed by a machinist, maintenance technician, or qualified trade professional using a standard tap wrench. Power down and de-energize any equipment before performing thread repair on components. Apply cutting fluid to the tap and workpiece to reduce heat and extend tool life during hand tapping. Follow the tap manufacturer's guidelines for proper STI drill size selection before tapping.