Osg 1986402 Spiral Flute Tap M8x1.25 Bottoming 6H Hss

Product Description

The OSG 1986402 is a spiral flute tap designed for cutting M8x1.25 metric coarse internal threads in a wide range of ferrous and non-ferrous materials. It features a bottoming chamfer, making it the right choice when threads must run close to the bottom of a blind hole. The 52-degree helix angle drives chips up and out of the flute efficiently, reducing the risk of chip packing in blind-bore applications. Built from high-speed steel with an elektraLUBE coating, the 1986402 delivers consistent performance in production and maintenance tapping operations. It carries a 6H class of fit and a D5 thread limit, ensuring threads meet standard tolerance requirements.

This tap is suited for tapping blind holes in aluminum, cast aluminum, cast iron, low-carbon steel, medium-carbon steel, and high-carbon steel. The bottoming chamfer and spiral flute geometry make it particularly effective in CNC machining centers, drill presses, and manual tapping setups where full thread depth near the bottom of a hole is required. The right-hand thread direction and right-hand flute direction match standard toolholder configurations.

Key Features

• Bottoming chamfer for threading close to the base of blind holes
• 52-degree helix angle promotes upward chip evacuation in blind-bore tapping
• elektraLUBE coating reduces friction and extends tool life across ferrous and non-ferrous materials
• High-speed steel construction provides toughness for a broad range of workpiece materials
• 6H class of fit and D5 thread limit meet standard metric tolerance requirements
• No coolant-through requirement simplifies toolholder selection

Compatibility

Designed for cutting M8x1.25 metric coarse right-hand threads in aluminum, cast aluminum, cast iron, high-carbon steel, low-carbon steel, and medium-carbon steel workpieces. Part of OSG Series 143.

Installation Notes

Tap installation and operation should be performed by a qualified machinist familiar with thread-cutting tooling. Power down and lock out any machine spindle before loading or unloading the tap. Use a properly sized tap wrench or collet chuck rated for the shank diameter to ensure concentricity and prevent tap breakage. Apply an appropriate cutting fluid for the workpiece material, and inspect the tap for wear or chipping before each use.