Osg 1406401 Spiral Flute Tap 4-40 Unc Plug Hss

Product Description

The OSG 1406401 is a spiral flute tap designed for cutting 4-40 UNC internal threads in a wide range of ferrous and non-ferrous metals. Built from high-speed steel with a steam oxide coating, it features a plug chamfer and a 50-degree helix angle that evacuates chips efficiently in through-hole and blind-hole applications. The H2 thread limit holds tight tolerances for 2B and 3B class-of-fit threads. At 1.875 inches overall length and a shank diameter of 0.141 inches, it fits standard tap holders and machine spindles used by machinists, tool-and-die makers, and maintenance technicians across industrial and commercial settings.

This tap is suited for threading operations in aluminum, cast aluminum, cast iron, low-carbon steel, medium-carbon steel, and high-carbon steel. The right-hand spiral flute pulls chips up and out of the hole, making it particularly effective in CNC tapping cycles and hand-tapping setups where chip management is a concern. The plug chamfer provides a gradual thread lead-in, distributing cutting load across the first several threads rather than concentrating it at the tip.

Key Features

• 4-40 UNC thread form with H2 thread limit for 2B and 3B class-of-fit tolerance control
• 50-degree right-hand helix angle promotes upward chip evacuation in blind and through holes
• Steam oxide coating reduces friction and improves lubrication retention during cutting
• High-speed steel construction provides durability across a broad range of workpiece materials
• Plug chamfer distributes cutting forces over multiple threads for controlled thread lead-in
• Compact 1.875-inch overall length fits standard tap chucks and quick-change holders

Compatibility

Designed for use in aluminum, cast aluminum, cast iron, low-carbon steel, medium-carbon steel, and high-carbon steel workpieces requiring 4-40 UNC threads at 2B or 3B class of fit.

Installation Notes

Installation is performed by machinists or maintenance technicians using a tap wrench, tapping head, or CNC rigid-tapping spindle. Secure the workpiece firmly before starting and align the tap perpendicular to the hole to avoid thread misalignment or tap breakage. Apply a suitable cutting fluid or tapping compound for the workpiece material before and during the operation. Reverse the tap periodically when hand-tapping to break chips and prevent binding.