Osg 1232605 Spiral Point Tap 1/2-20 Unf Tin Hss

Product Description

The OSG 1232605 is a spiral point tap designed for cutting right-hand internal threads in a range of ferrous and non-ferrous materials. It produces a 1/2-20 UNF thread form to a 3B class of fit and carries an H3 thread limit for consistent tolerance control. Manufactured from high-speed steel and finished with a titanium nitride (TiN) coating, the tap offers improved wear resistance and reduced friction during the threading operation. With three flutes and a plug chamfer, it is suited for through-hole tapping applications where chips are pushed forward ahead of the tap. Licensed machinists and toolroom technicians are the primary users of this tap.

This tap is intended for through-hole threading in production and job-shop environments. It handles a broad material range including low-carbon steel, medium-carbon steel, high-carbon steel, hardened steel, cast iron, aluminum, and cast aluminum. The plug chamfer requires several thread leads to engage before full-form threads are cut, making it appropriate for through holes with sufficient depth. It is not intended for blind-hole applications where a bottoming tap would be required.

Key Features

• 1/2-20 UNF thread form with 3B class of fit for standard tolerance internal threading
• H3 thread limit provides controlled oversize for plating allowance or consistent fit
• TiN coating increases surface hardness and extends tool life in abrasive materials
• Three-flute spiral point design pushes chips forward, reducing clogging in through-hole applications
• Plug chamfer with multi-lead entry eases thread start and reduces tap breakage risk
• No coolant-through feature; external coolant or cutting fluid application applies

Compatibility

Designed for through-hole tapping of 1/2-20 UNF threads in aluminum, cast aluminum, cast iron, low-carbon steel, medium-carbon steel, high-carbon steel, and hardened steel workpieces. Compatible with standard tap holders and collet chucks sized for a 0.367-inch shank diameter.

Installation Notes

This tap is installed and operated by machinists, toolroom technicians, or maintenance professionals using a drill press, CNC machining center, or hand tap wrench. Ensure the pilot hole is drilled to the correct tap drill diameter for 1/2-20 UNF before threading. Apply appropriate cutting fluid or tapping compound for the workpiece material to reduce heat and extend tool life. Never force a tap; if resistance increases unexpectedly, back off and clear chips before continuing.