Osg 1704901 Spiral Flute Tap 1/2-13 Unc Modified Bottoming

Product Description

The OSG 1704901 is a spiral flute tap designed to cut 1/2-13 UNC right-hand internal threads in demanding materials. Built from powdered metal with a steam oxide coating, this tap handles alloy steel, stainless steel, hardened steel, titanium, and high-nickel alloys. The modified bottoming chamfer allows threading close to the bottom of blind holes. With a 15-degree helix angle and 3 right-hand spiral flutes, the tool evacuates chips efficiently from the cutting zone, reducing galling and tap breakage in tough materials. Overall length is 3.375 inches. This is an H5 thread limit tap, producing a 2B class of fit.

This tap is suited for machine tapping operations in CNC machining centers, drill presses, and tapping heads used in metalworking shops and maintenance environments. The modified bottoming geometry is preferred when thread depth requirements push close to the hole bottom, such as in fixture plates, structural components, and precision assemblies. Licensed machinists, tool-and-die makers, and maintenance technicians working with difficult alloys will find this tool appropriate for high-torque, low-speed tapping setups. Coolant-through is not supported; external flood coolant or cutting oil should be used to manage heat in the cut.

Key Features

• 1/2-13 UNC right-hand thread form with H5 thread limit for consistent 2B class of fit
• Modified bottoming chamfer for threading near the bottom of blind holes
• 3 right-hand spiral flutes at 15-degree helix angle for upward chip evacuation
• Powdered metal construction for increased wear resistance in hard and abrasive materials
• Steam oxide coating reduces friction and improves lubricity at the cutting edge
• Rated for alloy steel, stainless steel, hardened steel, titanium, and high-nickel alloys

Compatibility

Designed for machine tapping applications requiring 1/2-13 UNC internal threads in alloy steel, stainless steel, hardened steel, titanium, and high-nickel alloy workpieces. Part of OSG Series 313.

Installation Notes

Installation should be performed by a qualified machinist using a rigid tapping holder or floating tap holder appropriate for the machine setup. Power down and secure the workpiece before tool changes. Use appropriate cutting fluid or flood coolant rated for the workpiece material, as coolant-through is not available on this tap. Do not exceed the recommended surface speed for the material being tapped, and ensure the tap is properly aligned with the pre-drilled pilot hole to avoid deflection and breakage.