Osg 12700300 Spiral Point Sti Tap M3 X 0.5 Metric Hss

Product Description

The OSG 12700300 is a spiral point STI tap designed for tapping metric threads in steel, cast iron, and similar materials. It cuts an M3 x 0.5 thread profile to a 6H class of fit with a D2 thread limit. The plug chamfer style makes it well-suited for through-hole applications, where the spiral point pushes chips ahead of the tap rather than packing them behind it. Built from high-speed steel with a bright, uncoated finish, this tap is a standard production tool used by machinists, tool and die makers, and maintenance technicians across general manufacturing and repair environments. Overall length is 2.125 inches with a 0.75-inch thread length.

This tap is intended for use in through-hole tapping operations on metric M3 x 0.5 threaded inserts, consistent with STI (Screw Thread Insert) applications. STI taps are used to create the oversize internal thread that accepts a helical wire insert, such as those used when repairing stripped threads or when installing inserts into softer base materials. The 2-flute design and plug chamfer allow smooth entry and consistent chip evacuation in production or repair settings. It is appropriate for hand or machine tapping in light-duty to medium-duty applications.

Key Features

• M3 x 0.5 metric thread size for STI insert applications
• Plug chamfer promotes chip-forward evacuation in through-hole work
• High-speed steel construction provides durability in general machining
• 6H class of fit with D2 thread limit for consistent insert thread tolerance
• 2-flute geometry suited for light-to-medium duty tapping
• Bright, uncoated finish compatible with standard cutting fluids

Compatibility

Designed as an OEM-style replacement spiral point STI tap for M3 x 0.5 metric thread insert applications in through-hole configurations. Consult insert manufacturer specifications to confirm tap series compatibility before use.

Installation Notes

This tap should be installed by a machinist or qualified maintenance technician using appropriate tapping fluid for the workpiece material. Secure the workpiece fully before tapping and align the tap perpendicular to the hole to avoid tap breakage or thread distortion. Power down all equipment before performing any manual thread repair operations in a live machine. Do not force the tap if resistance increases sharply, as this indicates chip packing or misalignment.