Kennametal 5689876 Spiral Flute Tap 5/16-18 Unc 2 Flute

Product Description

The KENNAMETAL 5689876 is a spiral flute tap designed for cutting internal threads in aluminum and non-ferrous materials. This tap carries a 5/16-18 UNC thread form, a modified bottoming chamfer for threading close to the bottom of a blind hole, and a multi-layer TiN/CrC/C coating that reduces built-up edge when cutting soft, gummy alloys. The right-hand, 2-flute fast-spiral configuration at a 45-degree helix angle evacuates chips upward out of the hole, keeping the cutting zone clear. Overall length is 3.54 inches with a thread length of approximately 0.59 inches (15 mm). The tap conforms to an H3 thread limit and a 3B class of fit, making it suitable for standard-tolerance UNC threaded assemblies.

This tap is intended for production and maintenance tapping operations in aluminum wrought alloys and other non-ferrous materials. The modified bottoming chamfer allows threading into shallow blind holes where a standard or plug chamfer cannot reach full thread depth. It is used in machine tapping setups on CNC machining centers, tapping heads, and rigid-tapping capable lathes. The fast-spiral flute geometry is particularly effective at preventing chip packing when running at the elevated speeds that aluminum machining typically demands. Coolant-through capability is not present on this tap, so external flood or mist coolant is the recommended approach.

Key Features

• 5/16-18 UNC thread form with H3 thread limit and 3B class of fit for standard-tolerance assemblies
• Modified bottoming chamfer allows threading near the bottom of blind holes
• 45-degree right-hand fast-spiral flutes evacuate chips upward to reduce packing in aluminum
• Multi-layer TiN/CrC/C coating minimizes built-up edge and extends tool life in non-ferrous applications
• Vanadium high speed steel base material provides wear resistance at elevated cutting temperatures
• Shank diameter of 0.318 inches suits standard tap holders and collet chucks for this size range

Compatibility

Designed for use in aluminum wrought alloys and non-ferrous materials (Primary Workpiece Material Code: N). Belongs to KENNAMETAL Series T682. Intended for machine tapping applications requiring a 5/16-18 UNC, 3B class of fit thread in blind-hole configurations.

Installation Notes

This tap is installed by machinists or toolroom technicians in a rigid-tapping holder, floating tap holder, or dedicated tapping head rated for the appropriate torque range. Before tool changes, ensure the spindle is fully stopped and the machine is in a safe state per shop lockout/tagout procedures. Verify that the tap holder taper and collet bore match the 0.318-inch shank diameter before clamping. External flood or mist coolant directed at the cutting zone is recommended, as this tap does not have coolant-through capability.