Hertel K007048AS Hand Sti Tap 1/4-20 Unc H2 3 Flutes

Product Description

The HERTEL K007048AS is a hand STI tap designed for cutting internal threads in pre-drilled holes to accept Helicoil-style thread inserts. It produces a 1/4-20 UNC thread profile to the H2 tolerance limit, giving machinists and maintenance technicians a close-tolerance fit for insert installation. The tap features 3 flutes and a plug chamfer that eases entry into through-holes and blind holes with adequate depth. Manufactured from high-speed steel with a bright, uncoated finish, it delivers durability across a range of common work-holding and repair applications. Overall length is 2-23/32 inches with a thread length of 1-1/8 inches.

This tap is used in thread repair and thread-insert installation work across industrial maintenance, manufacturing, and general machining environments. The plug chamfer style makes it suited for through-holes and deeper blind holes where a gradual cutting lead is acceptable. Technicians performing stripped-thread repairs on aluminum, mild steel, and similar materials will find this tap appropriate for preparing the bore before driving a helical thread insert. It is a hand-operated tap intended for use with a tap wrench or T-handle, not for machine tapping operations.

Key Features

• 1/4-20 UNC thread form with H2 tolerance limit for precise insert fitment
• Plug chamfer provides gradual cutting lead suitable for through-holes and deeper blind holes
• 3-flute geometry promotes chip clearance during hand tapping
• High-speed steel construction withstands repeated use in steel, aluminum, and similar materials
• Bright uncoated finish allows easy visual inspection of cutting edges
• Helicoil reference number 4CPB for cross-referencing with insert installation kits

Compatibility

Designed for use in STI thread insert applications referencing Helicoil reference number 4CPB. Intended for hand tapping operations requiring a 1/4-20 UNC H2 tap to prepare holes for helical thread inserts.

Installation Notes

Installation is performed by hand using a tap wrench or T-handle driver; do not use in a powered machine tapping setup unless the tap is specifically rated for it. Ensure the workpiece is securely clamped and the pilot hole is drilled to the correct diameter for a 1/4-20 STI thread before starting. Apply cutting fluid appropriate to the workpiece material to extend tap life and reduce the risk of breakage. Follow standard tap alignment practices to avoid cross-threading or tap breakage in the bore.