Osg 1012201 Straight Flute Tap 4-40 Unc Hss Oxide

Product Description

The OSG 1012201 is a straight flute tap designed for cutting 4-40 UNC internal threads in a range of metallic workpiece materials. It features three flutes with a plug chamfer, making it well suited for through-hole tapping applications where chips can be pushed ahead of the cutting edge. The tap is manufactured from high-speed steel with an oxide coating for added surface hardness and corrosion resistance. With an overall length of 1.875 inches and a thread length of 0.37 inches, this tap is compact enough for use in tight spaces. It is installed by machinists, tool-and-die makers, and maintenance technicians working in shop or field environments.

This tap is used for creating 4-40 UNC threads in aluminum, cast aluminum, cast iron, high-carbon steel, low-carbon steel, and medium-carbon steel workpieces. The plug chamfer entry makes it a standard choice for production tapping and general maintenance work. It is suitable for both machine tapping and careful hand tapping with an appropriate tap handle or machine spindle. The H2 thread limit designation ensures the finished threads fall within 2B and 3B class-of-fit tolerances, which are the standard fits for most fastener applications in these size ranges.

Key Features

• 4-40 UNC thread profile with right-hand thread direction
• Plug chamfer for through-hole tapping
• Three-flute straight design for chip clearing in through holes
• High-speed steel construction for durability across a range of metals
• Oxide coating for improved surface hardness and corrosion resistance
• H2 thread limit for 2B and 3B class-of-fit accuracy

Compatibility

Suitable for tapping 4-40 UNC threads in aluminum, cast aluminum, cast iron, high-carbon steel, low-carbon steel, and medium-carbon steel workpieces. Part of OSG Series 102.

Installation Notes

Secure the workpiece firmly before tapping and ensure the tap is properly aligned with the drilled pilot hole to prevent tap breakage. Use appropriate cutting fluid or tapping compound for the workpiece material to extend tap life and improve thread finish. When machine tapping, set spindle speed according to the material being tapped and use a tapping head where reversing is required. Replace worn taps before thread quality degrades to avoid rework.