Osg 1211401 Spiral Point Tap 4-40 Unc 2 Flute Hss

Product Description

The OSG 1211401 is a spiral point tap designed for cutting 4-40 UNC internal threads in a wide range of ferrous and non-ferrous materials. Built from high-speed steel with a steam oxide coating, this plug-chamfer tap drives chips forward ahead of the cutting zone, making it well suited for through-hole tapping applications. It features 2 flutes, a right-hand thread direction, and an H3 thread limit for consistent tolerance control. Overall length is 1.875 inches with a thread length of 0.319 inches (approximately 9/16 inches) and a shank diameter of 0.141 inches. Licensed machinists, tool and die makers, and maintenance technicians are the primary users.

This tap is intended for through-hole tapping in materials including aluminum, cast aluminum, cast iron, low-carbon steel, medium-carbon steel, high-carbon steel, and hardened steel. The plug chamfer provides a gradual lead-in, making it a practical choice for production and maintenance tapping operations where through-holes are standard. It is part of OSG Series 105 and is sold individually.

Key Features

• Spiral point geometry pushes chips forward, reducing clogging in through-hole applications
• High-speed steel construction provides durability across a broad range of work materials
• Steam oxide coating improves lubricity and corrosion resistance during cutting
• H3 thread limit ensures consistent fit within standard 4-40 UNC tolerance ranges
• Plug chamfer (3-5 thread lead) allows gradual thread engagement and is suitable for most through-hole jobs
• Right-hand thread direction; no coolant-through requirement simplifies setup

Compatibility

Designed as a direct-use spiral point tap for 4-40 UNC through-hole applications in aluminum, cast aluminum, cast iron, low-carbon steel, medium-carbon steel, high-carbon steel, and hardened steel workpieces.

Installation Notes

Tapping should be performed by a qualified machinist or maintenance technician using a properly aligned tap holder or CNC tapping head. Power down and secure the workpiece before beginning. Apply cutting fluid appropriate for the work material to extend tap life and improve thread quality. Do not reverse the tap under power without confirming the machine is set for reversing-tap mode, and never force a tap that has stalled in the hole.