Osg 1431000 Spiral Flute Tap 3/8-24 Unf 3 Flute Hss

Product Description

The OSG 1431000 is a spiral flute tap designed to cut 3/8-24 UNF internal threads in a wide range of metals. It features a plug chamfer for through-hole and moderately deep blind-hole applications and is ground to an H3 thread limit for a 3B class of fit. The 50-degree helix angle pulls chips up and out of the flute, making it well-suited for materials that produce stringy or continuous chips. Manufactured from high-speed steel with a bright uncoated finish, it delivers reliable performance in production and maintenance tapping operations. Installation is performed by machinists and toolroom technicians using standard tapping equipment.

This tap is intended for tapping 3/8-24 UNF threads in aluminum, cast aluminum, cast iron, low-carbon steel, medium-carbon steel, and high-carbon steel. The plug chamfer style makes it a general-purpose choice for through-holes or blind holes where there is sufficient relief at the bottom. With a 3B class of fit and H3 thread limit, it produces threads that accept standard 3A fasteners within UNF tolerance requirements. It is suited for both manual and machine tapping setups in job-shop, production, and maintenance-repair environments.

Key Features

• 3/8-24 UNF thread form with plug chamfer for versatile through-hole and blind-hole tapping
• 50-degree right-hand spiral flute evacuates chips upward, reducing recutting in ductile materials
• H3 thread limit and 3B class of fit for consistent tolerance control with standard 3A fasteners
• High-speed steel construction with bright uncoated finish
• Right-hand thread direction; no coolant-through feature
• Compatible with aluminum, cast iron, low-, medium-, and high-carbon steel workpiece materials

Compatibility

Designed for tapping 3/8-24 UNF threads in aluminum, cast aluminum, cast iron, low-carbon steel, medium-carbon steel, and high-carbon steel. Part of OSG Series 107.

Installation Notes

This tap is installed and used by machinists and toolroom technicians using a tapping machine, drill press, or CNC machining center set to the correct spindle speed for the workpiece material. Secure the tap in a properly sized tap holder or chuck before use. Ensure the pilot hole is drilled to the correct tap drill diameter for 3/8-24 UNF before tapping. Apply an appropriate cutting fluid for the workpiece material to extend tap life and improve thread finish.