Kennametal 1542159 Spiral Point Tap 1/4-20 Unc Hss

Product Description

The KENNAMETAL 1542159 is a spiral point tap designed for cutting right-hand internal threads in through-hole and shallow-bottoming applications. It produces a 1/4-20 UNC thread to a Class 3B fit with an H3 thread limit, making it suitable for work requiring close tolerance. The tap is manufactured from high speed steel (HSS) with a bright, uncoated finish and features a 2-flute spiral point geometry that pushes chips ahead of the cutting zone. Overall length is 2.5 inches with a 1.0-inch thread length. A shank diameter of 0.255 inches fits standard tap holders and chucks. Licensed machinists and tool-and-die technicians are the primary users.

This tap is well-suited for threading cast iron and non-ferrous metals in production and maintenance machining environments. The spiral point design is most effective in through-hole applications where chips can exit freely, but the bottoming chamfer also allows threading close to the bottom of a blind hole when needed. Typical use cases include general fabrication, repair work, and CNC or manual tapping operations on 1/4-20 fastener holes in cast iron components, aluminum, brass, and similar non-ferrous workpieces.

Key Features

• 1/4-20 UNC thread form, Class 3B fit, H3 thread limit for close-tolerance applications
• Spiral point geometry pushes chips forward, reducing chip packing in through-hole operations
• Bottoming chamfer allows threading close to the base of a blind hole
• High speed steel construction provides toughness and wear resistance in cast iron and non-ferrous metals
• Bright, uncoated finish maintains dimensional predictability with standard cutting fluids
• Right-hand cut, no coolant-through requirement — compatible with manual and CNC tapping setups

Compatibility

Rated for use in cast iron and non-ferrous metals. Part of the KENNAMETAL Series 5302 tap line. Designed as a direct-fit replacement for standard 1/4-20 UNC spiral point taps in matching tap holders sized for a 0.255-inch shank diameter.

Installation Notes

Tapping should be performed by a qualified machinist following applicable shop safety procedures. Secure the workpiece fully before starting and apply an appropriate cutting fluid for the material being tapped. Ensure the tap is aligned perpendicular to the workpiece surface to avoid thread distortion or tap breakage. Do not reverse the tap under power without confirming the machine is set for proper back-out to avoid damage to the threads or tool.