Osg 1719801 Spiral Flute Tap 1/4-20 Unc 3 Flute 2B

Product Description

The OSG 1719801 is a spiral flute tap designed for threading 1/4-20 UNC holes in difficult-to-machine materials. It features a modified bottoming chamfer, H5 thread limit, and a 2B class of fit, making it suited for applications that require tight tolerance internal threads. Constructed from powdered metal and finished with a steam oxide coating, the tap provides improved lubricity and wear resistance compared to uncoated tooling. With a 10-degree helix angle and three right-hand flutes, it evacuates chips efficiently in blind-hole applications. Overall length is 2.5 inches and the tap weighs approximately 0.034 pounds.

This tap is built for threading stainless steel, hardened steel, titanium, and high-nickel alloys — materials that demand higher-performance tooling than standard high-speed steel taps can reliably handle. It is part of the OSG Series 313NI, which targets work in demanding industrial and aerospace-adjacent environments. Typical applications include blind-hole tapping on machined components, fixtures, and assemblies where thread quality and tool life in tough materials are critical. Licensed machinists, tool and die makers, and maintenance mechanics are the primary users.

Key Features

• Modified bottoming chamfer for threading close to the bottom of blind holes
• Powdered metal construction for improved toughness and wear resistance in hard materials
• Steam oxide coating reduces friction and improves chip flow
• H5 thread limit for controlled 2B class of fit internal threads
• 10-degree right-hand helix angle promotes chip ejection in blind-hole tapping
• Rated for use in stainless steel, hardened steel, titanium, and high-nickel alloys

Compatibility

Designed for cutting 1/4-20 UNC right-hand internal threads in stainless steel, hardened steel, titanium, and high-nickel alloy workpieces. Suitable for use in standard tap holders and floating holders sized for a 0.255-inch shank diameter.

Installation Notes

Secure the workpiece fully before tapping and confirm the tap holder is properly aligned to the hole centerline to avoid tap breakage. Use appropriate cutting fluid or tapping compound recommended for the specific workpiece material, particularly for stainless steel and titanium. Power down or disengage the spindle before manually inspecting thread depth in blind holes. Dispose of worn taps per shop safety protocols — powdered metal tooling can fracture rather than deform when overloaded.