Osg 1748401 Spiral Flute Tap 4-40 Unc Vanadium Hss

Product Description

The OSG 1748401 is a spiral flute tap designed for cutting internal threads in a range of ferrous materials. Built from vanadium high-speed steel with a steam oxide coating, it produces 4-40 UNC right-hand threads with a modified bottoming chamfer for threading close to the bottom of blind holes. The 45-degree helix angle promotes chip evacuation up the flute, reducing the risk of chip packing in tight bores. With an overall length of 1.875 inches and a thread length of 0.197 inches, this tap is suited for precision threading operations in small fastener applications across machining and fabrication work.

This tap is intended for use on stainless steel, high-carbon steel, low-carbon steel, and medium-carbon steel. The modified bottoming chamfer makes it appropriate for blind-hole applications where full thread engagement near the bottom of the hole is required. The H6 thread limit designation indicates a tight tolerance class, making it a fit for applications that demand consistent thread form and dimensional control. It is commonly used in machine shops, toolrooms, and production environments where small-diameter tapping is performed on ferrous workpieces.

Key Features

• 4-40 UNC thread form with right-hand thread direction
• Modified bottoming chamfer for threading near the bottom of blind holes
• 45-degree helix angle promotes upward chip evacuation
• Vanadium high-speed steel construction for wear resistance in ferrous materials
• Steam oxide coating reduces friction and improves chip flow
• H6 thread limit for tight, consistent tolerance class threads

Compatibility

Designed as a direct-use tap for 4-40 UNC threading applications in stainless steel, high-carbon steel, low-carbon steel, and medium-carbon steel workpieces.

Installation Notes

This tap should be installed in a tapping chuck or CNC toolholder appropriate for the 0.141-inch shank diameter. Power down any machine spindle and secure the workpiece before setup. Use a cutting fluid or tapping compound rated for the workpiece material to extend tool life and improve thread quality. Coolant-through operation is not supported on this tap.