Kennametal 4131075 Spiral Flute Tap 5/16-18 Unc Bottoming H3

Product Description

The KENNAMETAL 4131075 is a spiral flute bottoming tap designed for cutting 5/16-18 UNC internal threads in non-ferrous metals. It features three right-hand flutes with a fast flute style and a 52-degree helix angle, which efficiently evacuates chips upward out of the hole — a critical advantage in blind-hole applications. The tap is manufactured from vanadium high speed steel and carries a straw finish. Thread limit is H3, and the class of fit is 3B. Overall length is 2.72 inches, with a thread length of 0.685 inches and a shank diameter of 0.318 inches. Licensed machinists, toolroom technicians, and CNC operators typically deploy this tap for precision threading operations.

This bottoming tap is suited for blind-hole threading in non-ferrous materials such as aluminum, brass, copper, and similar alloys. The bottoming chamfer — typically 1 to 2 thread leads — allows threads to be cut as close to the bottom of a blind hole as possible. It is intended for use in tapping heads, CNC machining centers, drill presses, or hand-tapping operations where tight thread tolerance and full thread depth are required. The 3B class of fit delivers a standard tolerance appropriate for most mechanical fastening applications.

Key Features

• Bottoming chamfer for full thread depth in blind holes
• 52-degree helix angle with fast flute style for upward chip evacuation
• H3 thread limit for 3B class of fit tolerance
• Right-hand thread and right-hand flute direction
• Straw finish on vanadium high speed steel construction
• No coolant-through requirement — suitable for standard tapping setups

Compatibility

Designed for threading 5/16-18 UNC blind holes in non-ferrous metals. Fits standard 5/16-inch tap holders, tapping chucks, and collet-style toolholders compatible with a 0.318-inch shank diameter.

Installation Notes

This tap should be installed in a properly sized tap holder or tapping chuck rated for the shank diameter before use. Ensure the workpiece is securely fixtured and the spindle is aligned with the hole axis to prevent tap breakage. Apply an appropriate cutting fluid for non-ferrous materials to extend tool life and improve thread finish. Always power down or disengage the spindle before changing or inspecting the tap.