Osg 1232401 Spiral Point Tap 1/2-13 Unc Plug Hss

Product Description

The OSG 1232401 is a spiral point plug tap designed for threading 1/2-13 UNC holes in a wide range of ferrous and non-ferrous materials. Manufactured from high-speed steel (HSS) with a steam oxide coating, this tap offers reliable performance in through-hole threading applications. It features 3 flutes with a plug chamfer that guides the tap into the workpiece and progressively cuts threads to a 3B class of fit. The H3 thread limit provides controlled oversize for plated or tight-tolerance applications. Overall length is 3.375 inches with a thread length of 0.941 inches and a shank diameter of 0.367 inches. Installed by machinists and maintenance technicians in shop and field environments.

This tap is suited for through-hole threading operations in materials including aluminum, cast aluminum, cast iron, low-carbon steel, medium-carbon steel, high-carbon steel, and hardened steel. The plug chamfer style requires a started hole with adequate clearance beyond the full thread length, making it most appropriate for through-hole work rather than blind-hole applications. The steam oxide coating reduces friction and helps resist corrosion during storage and use. It is part of the OSG Series 105 product line and is intended for use in manual tap handles, tapping arms, or CNC tapping operations with right-hand rotation.

Key Features

• 1/2-13 UNC thread form with 3B class of fit and H3 thread limit for controlled tolerance
• 3-flute spiral point design pushes chips ahead of the tap, keeping the flutes clear in through-hole applications
• High-speed steel construction supports use across a broad range of material hardness levels
• Steam oxide coating reduces friction and provides light corrosion protection
• Plug chamfer for progressive thread engagement and easier starting
• Right-hand thread direction; no coolant-through feature required for general-purpose use

Compatibility

Designed as a general-purpose OEM-style spiral point plug tap for 1/2-13 UNC through-hole threading in aluminum, cast aluminum, cast iron, low-carbon steel, medium-carbon steel, high-carbon steel, and hardened steel workpieces.

Installation Notes

This tap is installed by machinists or maintenance technicians using a tap handle, tapping arm, or CNC machining center set to right-hand rotation. Always ensure the pilot hole is drilled to the correct tap drill diameter for 1/2-13 UNC before threading. Secure the workpiece firmly and apply appropriate cutting fluid for the material being tapped. Do not reverse a spiral point tap while chips are packed in the flutes, as this can cause breakage.