Osg 1012208 Straight Flute Tap 4-40 Unc Ticn Hss

Product Description

The OSG 1012208 is a straight flute plug tap designed to cut 4-40 UNC internal threads in a wide range of metallic workpiece materials. Manufactured from high-speed steel and finished with a titanium carbonitride (TiCN) coating, the tap offers improved surface hardness and wear resistance over uncoated HSS tooling. It features three straight flutes and a plug chamfer, making it suited for through-hole and blind-hole threading where chips can be managed manually or with coolant flush. The H2 thread limit holds tight pitch diameter control for 2B and 3B class-of-fit threads. Overall length is 1.875 inches with a thread length of 0.5625 inches (9/16 inches).

This tap is intended for use in machine shop, maintenance, repair, and production threading operations. Typical applications include tapping aluminum, cast aluminum, cast iron, low-carbon steel, medium-carbon steel, and high-carbon steel workpieces. It is commonly installed in CNC machining centers, drill presses, or hand-tapping fixtures. The straight flute geometry is best suited for through-holes or short blind holes where chip evacuation is not a critical constraint.

Key Features

• TiCN coating increases surface hardness and extends tool life versus uncoated HSS
• Plug chamfer provides a gradual thread lead-in for through-hole and standard blind-hole applications
• H2 thread limit ensures consistent 2B and 3B class-of-fit compliance
• Three straight flutes maintain rigidity in small-diameter threading
• Right-hand thread direction - standard for most machine and hand-tapping setups
• No coolant-through requirement - compatible with flood coolant or dry cutting depending on material

Compatibility

Designed to cut 4-40 UNC threads in aluminum, cast aluminum, cast iron, low-carbon steel, medium-carbon steel, and high-carbon steel. Suitable for use with standard tap holders and collet chucks sized for a 0.141-inch shank diameter.

Installation Notes

This tap is installed by a machinist or tool-and-die technician in a compatible tap holder, collet, or tapping head. Ensure the machine spindle is at a safe stop and all motion is arrested before changing tooling. Use appropriate cutting fluid or coolant for the workpiece material to maximize tool life and thread quality. Do not reverse the tap without confirming the setup is configured for reversible tapping to avoid breakage in the hole.