Hertel K007255AS Hand Sti Tap M4 X 0.7 Metric Coarse Hss

Product Description

The HERTEL K007255AS is a hand STI tap designed for cutting M4 x 0.7 metric coarse thread inserts into pre-drilled holes. STI taps produce an oversized thread profile sized to accept helical thread inserts, restoring damaged threads or adding reinforced thread forms in soft base materials. This tap features a plug chamfer with 3 to 5 leading threads for easy starting and steady threading progression. It is manufactured from high speed steel (HSS) with a bright, uncoated finish, making it well suited for general-purpose tapping in steel, aluminum, and similar materials. Overall length is 2.375 inches. Machinists, maintenance technicians, and toolroom professionals use this tap for both production and repair applications.

The K007255AS is applied wherever M4 x 0.7 STI threads are required, including thread repair on stripped fastener holes, insert installation in thin-walled assemblies, and original thread creation in soft or medium-hardness workpieces. The plug chamfer style makes it the standard choice for through-hole applications and most blind-hole work where adequate clearance exists at the bottom of the bore. This is a hand-tap configuration intended for use with a tap wrench or standard tapping fixture rather than machine-driven tooling.

Key Features

• M4 x 0.7 metric coarse thread form for STI (Screw Thread Insert) applications
• Thread limit D1 for close-tolerance thread fits compatible with helical insert installation
• 3-flute geometry provides efficient chip clearance in a range of workpiece materials
• Plug chamfer (3 to 5 thread lead) suits through-holes and clearance blind holes
• High speed steel construction delivers durability in general-purpose hand-tapping use
• Bright uncoated finish — no coating stack to affect thread tolerance dimensions

Compatibility

Designed as a standard hand STI tap for use with M4 x 0.7 metric coarse helical thread inserts in hand-tapping applications.

Installation Notes

This tap is intended for hand operation using a tap wrench sized to the square shank. Secure the workpiece firmly before tapping and ensure the starting hole is drilled and chamfered to the correct STI tap drill diameter for M4 x 0.7. Apply cutting fluid appropriate to the workpiece material and back off the tap periodically to break chips and prevent tap breakage. Do not use this hand tap in a power driver without a floating tap holder, as rigid power driving increases breakage risk on small-diameter taps.