Osg 1431305 Spiral Flute Tap 7/16-14 Unc Bottoming Tin Hss

Product Description

The OSG 1431305 is a spiral flute bottoming tap designed for threading 7/16-14 UNC holes in a wide range of ferrous and non-ferrous metals. Built from high-speed steel (HSS) with a titanium nitride (TiN) coating, it delivers extended tool life and reduced friction in production threading applications. The tap features a 50-degree helix angle with 3 right-hand flutes, which efficiently evacuates chips upward — making it well suited for blind-hole threading where chip packing is a concern. The bottoming chamfer allows threads to be cut close to the bottom of a hole. Licensed machinists, toolroom technicians, and maintenance mechanics are the primary users.

This tap is used in general machining, fabrication, and maintenance operations where 7/16-14 UNC internal threads are required. The 3B class of fit makes it appropriate for standard commercial tolerances. Recommended material applications include aluminum, cast aluminum, cast iron, high-carbon steel, low-carbon steel, and medium-carbon steel. It is suited for both CNC tapping centers and manual drill press or hand-tapping operations where coolant-through tooling is not required.

Key Features

• Bottoming chamfer allows threading to within a few threads of the blind-hole floor
• 50-degree right-hand spiral flute design promotes upward chip evacuation in blind holes
• TiN coating reduces friction and extends tool life compared to uncoated HSS
• H3 thread limit for 3B class of fit — standard commercial tolerance range
• No coolant-through requirement — compatible with flood, mist, or paste lubricants
• Rated for aluminum, cast aluminum, cast iron, and low- to high-carbon steel applications

Compatibility

Designed for threading 7/16-14 UNC holes per the H3 thread limit and 3B class of fit specification. Compatible material applications as rated by the manufacturer include aluminum, cast aluminum, cast iron, high-carbon steel, low-carbon steel, and medium-carbon steel.

Installation Notes

Threading operations should be performed by a qualified machinist or toolroom technician following applicable shop safety procedures. Ensure the workpiece is securely fixtured and the spindle is properly aligned before engaging the tap to avoid tap breakage or cross-threading. Apply appropriate cutting fluid or tapping paste for the workpiece material — dry threading is not recommended for steel. When using in a CNC tapping center, verify the machine is programmed for synchronized rigid tapping at the correct pitch for 14 threads per inch.