Osg 1432905 Spiral Flute Tap 5/8-11 Unc Tin Hss

Product Description

The OSG 1432905 is a spiral flute tap designed for cutting internal 5/8-11 UNC threads in a range of metallic workpiece materials. Built from high-speed steel with a titanium nitride (TiN) coating, it delivers extended wear resistance compared to uncoated HSS taps. The bottoming chamfer style allows threading close to the bottom of blind holes where a plug or taper chamfer would leave unfinished threads. With a 50-degree helix angle and right-hand spiral flute geometry, it efficiently evacuates chips upward out of the hole during the cut. Licensed machinists, tool-and-die makers, and maintenance technicians are the typical users.

This tap is suited for production and maintenance threading operations in materials including low-carbon steel, medium-carbon steel, high-carbon steel, cast iron, aluminum, and cast aluminum. The 3B class of fit produces a standard tolerance internal thread appropriate for most commercial fastener applications. At 3.813 inches overall length, the tap accommodates standard tap holders and tapping heads found in manual and CNC machining environments. It is particularly useful when a through-hole application has been converted to a blind-hole requirement and full thread depth to the bottom is necessary.

Key Features

• Bottoming chamfer allows threading to within 1-2 threads of hole bottom in blind-hole applications
• 50-degree right-hand spiral flute geometry promotes upward chip evacuation, reducing re-cutting and tap breakage
• TiN coating improves surface hardness and lubricity for longer tool life on steel and cast iron
• 3B class of fit produces a standard commercial-tolerance internal thread for most fastener assemblies
• H3 thread limit provides controlled tolerance for consistent fit across production runs
• High-speed steel construction withstands moderate cutting heat without loss of edge integrity

Compatibility

Designed for threading 5/8-11 UNC blind holes in aluminum, cast aluminum, cast iron, low-carbon steel, medium-carbon steel, and high-carbon steel workpieces. Coolant-through capability is not supported; external cutting fluid application is required for best results in steel and cast iron.

Installation Notes

This tap is installed by a machinist or toolroom technician using a standard tap wrench, tapping stand, or CNC tapping head with a suitable tap holder for a 0.480-inch shank diameter. Ensure the workpiece is securely fixtured and the pilot hole is drilled to the correct tap drill diameter for 5/8-11 UNC before starting the tap. Apply cutting fluid appropriate for the workpiece material throughout the tapping operation. Reverse the tap periodically when tapping by hand to break and clear chips, especially in deeper blind holes.