Accupro T2644162B Spiral Flute Tap 4-40 2 Flute Modified Bottoming

Product Description

The ACCUPRO T2644162B is a spiral flute tap designed for threading 4-40 inch machine screw holes in production and repair applications. Built from 3% Vanadium High Speed Steel with a bright, uncoated finish, this tap delivers clean thread formation in a compact overall length of 1.87 inches. The modified bottoming chamfer allows threading close to the bottom of blind holes, making it well suited for tight-clearance fastener locations common in light manufacturing, electrical enclosures, and precision assembly work. It is installed by machinists and toolroom technicians using standard tap wrenches or CNC tapping heads.

This tap is designed for 4-40 unified coarse thread applications requiring a 2B class of fit, which represents a standard commercial tolerance suitable for most general-purpose threaded fastener assemblies. The two-flute spiral design with a 40-degree helix angle and fast flute style promotes chip evacuation in blind-hole tapping operations. The right-hand thread and right-hand flute configuration follow standard convention. Thread length is 6.00 millimeters. Typical applications include threading holes in thin aluminum panels, steel brackets, and electronic component housings.

Key Features

• 4-40 thread size with 2B class of fit for standard commercial fastener tolerance
• Modified bottoming chamfer for threading close to the bottom of blind holes
• 3% Vanadium High Speed Steel construction for wear resistance in production tapping
• 40-degree helix angle with fast flute style for improved chip evacuation
• Bright, uncoated finish suitable for use with cutting fluids or tapping compounds
• Compact 1.87-inch overall length for use in confined spaces

Compatibility

Designed as a standard replacement or production tap for 4-40 unified thread applications requiring a 2B class of fit in blind-hole configurations.

Installation Notes

Install using a calibrated tap wrench, tapping head, or CNC spindle set to the correct RPM for the workpiece material. Always apply an appropriate cutting fluid or tapping compound to reduce heat and extend tool life. Ensure the tap is properly aligned perpendicular to the work surface before beginning to thread. Inspect the tap for wear or chipping before each use, and never apply excessive torque on small-diameter taps to avoid breakage.