Kennametal 5689984 Spiral Flute Tap 5/16-18 Unc 3 Flute

Product Description

The KENNAMETAL 5689984 is a spiral flute tap designed for cutting 5/16-18 UNC internal threads in production and job-shop environments. It features a modified bottoming chamfer, allowing thread engagement close to the bottom of blind holes. The tap is manufactured from vanadium high speed steel with a cobalt-enhanced matrix and carries a multi-layer TiN/CrC/C coating that reduces friction and improves tool life in non-ferrous and light-alloy materials. With an H3 thread limit and 3B class of fit, it holds the tolerances required for standard fastener-grade threaded holes. Three right-hand spiral flutes with a 25-degree helix angle efficiently evacuate chips up and out of the hole during the tapping cycle.

This tap is suited for tapping aluminum cast alloy and similar non-ferrous materials in CNC machining centers, drill presses, and tapping machines. The modified bottoming chamfer makes it the correct choice when full thread depth is needed in blind holes with limited clearance. The right-hand flute direction and 25-degree helix angle promote smooth chip flow without coolant-through capability, making it appropriate for flood-cooled or lubricated setups in a machine shop or production line environment.

Key Features

• 5/16-18 UNC thread form, 3B class of fit with H3 thread limit for standard fastener-grade tolerance
• Modified bottoming chamfer for threading close to the base of blind holes
• Multi-layer TiN/CrC/C coating reduces friction and extends tool life in aluminum and light alloys
• 25-degree right-hand helix angle with 3 medium spiral flutes for efficient chip evacuation
• Vanadium high speed steel with cobalt construction for wear resistance under production cycle loads
• Series T686 design — 3.54-inch overall length with 0.318-inch shank diameter

Compatibility

Designed for use in aluminum cast alloy applications. Fits standard tap holders and tapping heads accepting a 0.318-inch shank diameter. Verify holder collet size and torque settings before use; no specific machine model compatibility is stated by the manufacturer for this part.

Installation Notes

This tap should be installed by a qualified machinist or tooling technician familiar with tapping operations and cutting-tool holder requirements. Secure the shank in a properly sized collet or tap holder and confirm alignment with the drilled pilot hole before engaging the spindle. Apply appropriate cutting fluid or flood coolant rated for the workpiece material — aluminum alloys typically require a lubricant rather than a dry cut. Never force a tap against the bottom of a blind hole without confirming available thread depth against the 1.38-inch tapping depth specification.