Osg 1206402 Spiral Point Tap 4-40 Unc Hss

Product Description

The OSG 1206402 is a spiral point plug tap designed for threading 4-40 UNC internal threads in through-hole applications. Made from high-speed steel (HSS) with an elektraLUBE coating, this tap is built for controlled chip ejection forward through the hole, reducing the risk of chip packing and thread damage. It features 2 flutes, a plug chamfer, H2 thread limit, and a 2B/3B class of fit, making it suitable for standard tolerance threaded holes requiring reliable engagement across a 9/16 inch thread length. Machinists and toolroom professionals use this tap in both manual and machine tapping operations.

The 1206402 is rated for use across a broad range of materials including aluminum, cast aluminum, cast iron, low-carbon steel, medium-carbon steel, high-carbon steel, and hardened steel. It is well-suited for production and maintenance environments where 4-40 UNC threads are required in through-hole configurations. The right-hand thread direction is standard for conventional tapping setups on mills, drill presses, and tapping arms. This tap does not support coolant-through delivery.

Key Features

• Spiral point geometry ejects chips forward, ideal for through-hole tapping
• elektraLUBE coating reduces friction and extends tool life across varied workpiece materials
• High-speed steel construction handles a wide range of ferrous and non-ferrous materials including hardened steel
• Plug chamfer provides a gradual thread start for smooth entry
• H2 thread limit and 2B/3B class of fit for standard tolerance threaded connections
• 9/16 inch thread length suits typical through-hole depths at this thread size

Compatibility

Designed for cutting 4-40 UNC internal threads in through-hole applications across aluminum, cast aluminum, cast iron, low-carbon steel, medium-carbon steel, high-carbon steel, and hardened steel workpieces. Compatible with standard 4-40 UNC tap holders and collet-style tapping chucks accepting the appropriate shank size for OSG Series 105 taps.

Installation Notes

This tap should be installed by a qualified machinist familiar with thread form requirements and tap holder specifications. Ensure the workpiece is properly secured and the spindle or tapping arm is aligned true to the hole axis before engaging the tap. Use appropriate cutting fluid for the workpiece material even though the elektraLUBE coating provides lubrication — additional fluid extends tool life in steel applications. Inspect the tap for wear or chipping before each use; a damaged tap can strip threads or break in the hole.