Kennametal 5703879 Spiral Flute Tap 1/4-20 Unc Bottoming 3B

Product Description

The KENNAMETAL 5703879 is a spiral flute tap designed for threading 1/4-20 UNC holes to a bottoming chamfer with a 3B class of fit. Manufactured from powdered metal vanadium high speed steel, it carries a multi-layer nitride and oxide coating suited for demanding cutting applications. The tap runs a right-hand, slow-helix flute geometry at a 10-degree helix angle across three flutes, with an overall length of 2.5 inches and a thread length of 0.44 inches (11.10 mm). It is used in applications involving high-temperature alloys and nickel alloys, where controlled chip evacuation and coating durability are critical. Licensed tradespeople and precision machinists install this tool in manual or CNC tapping operations.

This tap is rated for primary workpiece materials in the S-category, which covers high-temp alloys and nickel-based materials. The bottoming chamfer style allows threading close to the bottom of blind holes, making it well suited for tight-tolerance blind-hole applications in aerospace, defense, and industrial manufacturing environments. With a tapping depth of 1.00 inch (26.00 mm) and a shank diameter of 0.255 inches (6.48 mm), it fits standard tap holders used in production and maintenance machining operations.

Key Features

• Bottoming chamfer for threading close to the bottom of blind holes
• Multi-layer nitride and oxide coating for wear resistance in high-temp alloy materials
• 3 right-hand spiral flutes with 10-degree slow helix angle for controlled chip movement
• H3 thread limit with 3B class of fit for consistent thread tolerance
• Powdered metal vanadium high speed steel construction for increased toughness and edge retention
• No coolant-through requirement, compatible with standard external coolant delivery

Compatibility

Designed as an OEM-style threading tool for 1/4-20 UNC blind-hole tapping operations in high-temperature alloys and nickel alloys, classified under primary workpiece material code S. Part of the KENNAMETAL T694 series.

Installation Notes

Installation should be performed by a qualified machinist or toolroom technician using a properly sized tap holder or collet chuck matched to the 0.255-inch shank diameter. Ensure the machine spindle and workpiece are fully secured before tool engagement. Apply cutting fluid appropriate for the workpiece material to the tap and hole entry before beginning the tapping cycle. Do not exceed the rated tapping depth of 1.00 inch to avoid tool breakage in blind-hole applications.