Hertel K007186AS Hss Hand Sti Tap 7/8-14 Unf H3 4 Flute

Product Description

The HERTEL K007186AS is a high speed steel hand STI tap designed for cutting Screw Thread Insert (STI) threads in a variety of materials. This tap features a 7/8-14 UNF thread form with an H3 tolerance class, four flutes, and a plug chamfer to ease thread entry. The bright finish reduces friction during tapping and helps with chip removal. With an overall length of 5.125 inches and a thread length of 2.5 inches, it provides adequate reach for typical hand-tapping operations. It is intended for use by machinists and maintenance technicians who need to prepare holes for Helicoil or compatible wire thread inserts.

This tap is used in applications where a standard thread has been damaged or where added thread strength is required through the use of a wire thread insert. It is suited for both production and repair environments across industries such as aerospace, automotive, and general manufacturing. The STI thread form is oversized relative to the nominal thread to accommodate the insert, which upon installation produces a standard internal thread. This tap corresponds to Helicoil reference number 8193-14.

Key Features

• 7/8-14 UNF thread form with H3 tolerance class for consistent fit
• Four-flute geometry for balanced cutting and chip evacuation
• Plug chamfer provides a gradual lead-in for hand tapping operations
• Bright finish reduces friction and aids chip clearance
• High speed steel construction provides durability across a range of workpiece materials
• Sized for use with Helicoil or compatible STI insert systems (Helicoil reference 8193-14)

Compatibility

Compatible with Helicoil and similar wire thread insert systems requiring a 7/8-14 UNF STI oversize tap. Helicoil reference number 8193-14.

Installation Notes

Installation is typically performed by a machinist or maintenance technician using a standard tap wrench. The workpiece should be securely clamped and the pilot hole drilled to the STI oversize specification before tapping. Apply cutting fluid appropriate for the workpiece material and back off periodically to break chips. Refer to the insert manufacturer guidelines for correct hole diameter and insert installation procedure.