Hertel K007363AS Spiral Flute Sti Tap M8x1.25 Metric Coarse

Product Description

The HERTEL K007363AS is a high speed steel spiral flute STI tap designed for cutting M8x1.25 metric coarse threads in spark-eroded or oversized holes. With a 52-degree helix angle, the flute geometry pulls chips up and out of the hole during tapping, reducing the risk of chip packing in blind-hole applications. The bottoming chamfer allows threading closer to the bottom of a blind bore, making this tap a practical choice when full thread depth is required near the end of a hole. Three flutes provide a balance of chip clearance and cutting edge support. This tap is used by machinists, tool-and-die makers, and maintenance technicians working on metric-threaded assemblies.

This tap is suited for use in ferrous and non-ferrous metals where STI (Screw Thread Insert) thread forms are required, such as when installing helical wire inserts to repair or strengthen tapped holes in aluminum, cast iron, or steel components. The M8x1.25 thread size is common in automotive, aerospace, and general industrial maintenance work. The bright finish indicates an uncoated tool, appropriate for use with cutting fluid in standard production or repair environments. Thread limit D2 keeps tolerance within a controlled range suitable for standard STI insert fitment.

Key Features

• 52-degree helix angle promotes upward chip evacuation in blind-hole tapping
• Bottoming chamfer allows threading to near full depth in blind bores
• STI thread form sized for M8x1.25 helical wire thread insert installation
• Three flutes balance chip clearance with cutting edge rigidity
• High speed steel construction provides toughness across a range of work materials
• Thread limit D2 maintains controlled tolerance for consistent insert fitment

Compatibility

Designed as an OEM-style tooling option for applications requiring M8x1.25 metric coarse STI thread forms, compatible with standard helical wire thread insert systems using that thread size and pitch.

Installation Notes

Installation should be performed by a qualified machinist or maintenance technician using a properly sized tap wrench or machine tap holder. Apply an appropriate cutting fluid for the work material before and during tapping to reduce heat and extend tool life. Ensure the tap is aligned perpendicular to the workpiece surface before applying torque. Reverse the tap periodically to break chips when threading deep blind holes.