Osg 1432105 Spiral Flute Tap 1/2-13 Unc Bottoming Tin Hss

Product Description

The OSG 1432105 is a spiral flute bottoming tap designed for cutting right-hand internal threads to a 1/2-13 UNC standard in a Class 3B fit. Built from high-speed steel with a titanium nitride (TiN) coating, it delivers reduced friction and extended tool life across a range of ferrous and non-ferrous materials. The 3-flute spiral design with a 50-degree helix angle efficiently evacuates chips upward out of the hole, making it well-suited for blind-hole applications where chip packing is a concern. Overall length is 3.375 inches with a thread length of 0.96 inches. It carries a Thread Limit designation of H3, indicating a close-tolerance ground thread suitable for precision fastener applications.

This tap is used in machine shop, maintenance, and production environments where blind-hole tapping is required. The bottoming chamfer allows threading close to the bottom of a hole, which is critical when thread engagement depth is limited. Rated material applications include aluminum, cast aluminum, cast iron, high-carbon steel, low-carbon steel, and medium-carbon steel, covering the majority of structural and mechanical components encountered in trade and industrial settings. It is appropriate for use in CNC tapping cycles and manual tapping operations alike.

Key Features

• 1/2-13 UNC right-hand thread form with Class 3B fit tolerance
• 50-degree helix angle spiral flutes for upward chip evacuation in blind holes
• Bottoming chamfer for threading to near-full depth in blind-hole applications
• TiN coating reduces friction and increases tool life compared to uncoated HSS
• H3 thread limit for close-tolerance, precision thread production
• No coolant-through design; suitable for standard flooded or dry tapping setups

Compatibility

Rated for use in aluminum, cast aluminum, cast iron, high-carbon steel, low-carbon steel, and medium-carbon steel. Part of the OSG Series 107 spiral flute tap line.

Installation Notes

This tap is installed by machinists and tool-and-die professionals using a tap wrench, tapping head, or CNC rigid tapping cycle. Before tapping, ensure the pilot hole is drilled to the correct tap drill diameter for a 1/2-13 UNC thread and that the workpiece is securely fixtured. Apply an appropriate cutting fluid for the workpiece material to improve thread finish and tool life. Do not reverse the tap under load without first relieving chip pressure, particularly in deep blind holes.