Osg 1216401 Spiral Point Tap 4-40 Unc 2 Flute Hss

Product Description

The OSG 1216401 is a spiral point tap designed for cutting 4-40 UNC threads in a wide range of ferrous and non-ferrous materials. Built from high-speed steel with a steam oxide coating, it delivers reliable performance in production and repair threading applications. The plug chamfer style makes it suited for through-hole threading, pushing chips ahead of the cutting edge to reduce clogging. With an overall length of 1.875 inches and a thread length of 0.319 inches, this tap fits standard tap handles and machine setups used by machinists and maintenance technicians across industrial and commercial environments.

This tap is appropriate 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 2-flute spiral point geometry suits both hand tapping and machine tapping at moderate speeds. It carries an H5 thread limit designation, indicating a slightly oversize tolerance suitable for plated or coated fastener applications. Typical use cases include equipment maintenance, fixture fabrication, and production threading where a 4-40 UNC thread form is required.

Key Features

• 4-40 UNC thread form with right-hand thread direction
• 2-flute spiral point design pushes chips forward through the hole
• Plug chamfer for through-hole threading applications
• H5 thread limit with oversize classification for plated fastener clearance
• Steam oxide coating improves lubricity and corrosion resistance during cutting
• High-speed steel construction handles a broad range of workpiece materials

Compatibility

Designed as a direct-fit replacement or standard 4-40 UNC spiral point tap for use in manual tap handles, tapping heads, and CNC tapping operations requiring an H5 thread limit and plug chamfer geometry. Compatible with material applications including aluminum, cast aluminum, cast iron, low-carbon steel, medium-carbon steel, high-carbon steel, and hardened steel.

Installation Notes

Install in a properly sized tap handle or machine tapping chuck before use. Always ensure the workpiece is securely fixtured and the pilot hole is drilled to the correct tap drill size for 4-40 UNC threads prior to tapping. Apply cutting fluid appropriate for the workpiece material to extend tap life and improve thread quality. Do not reverse the tap under power; back out manually to clear chips when hand tapping.