Hertel K008086AS Straight Flute Tap 4-40 Unc Hss

Product Description

The HERTEL K008086AS is a straight flute tap designed to cut 4-40 UNC internal threads in a variety of workpiece materials. Built from high-speed steel with a bright, uncoated finish, this tap features three straight flutes and a taper chamfer to ease thread entry and reduce startup torque. It carries an H2 thread limit, which keeps tolerance control tight for 2B and 3B class-of-fit applications. Overall length is 1.875 inches. Right-hand thread direction is standard. Machinists and tool-and-die technicians use this tap for production threading in CNC machining centers, drill presses, and manual tapping operations.

This tap is suited for threading small-diameter holes in ferrous and non-ferrous metals, plastics, and similar materials where a 4-40 UNC thread form is required. The taper chamfer makes it well suited for through-hole applications where the tap can advance fully through the material. The straight flute geometry is most effective in short-chipping materials. It is a common choice in light manufacturing, instrumentation work, and general machining environments where 4-40 fasteners are specified.

Key Features

• 4-40 UNC thread form, right-hand thread direction
• Taper chamfer for smooth thread entry in through-hole applications
• Three straight flutes optimized for short-chipping materials
• H2 thread limit for consistent 2B and 3B class-of-fit tolerances
• High-speed steel construction for durability in general-purpose machining
• Bright, uncoated finish — no coating buildup concerns on small-diameter taps

Compatibility

Designed as a standard replacement straight flute tap for any application requiring a 4-40 UNC, H2, taper chamfer tap in high-speed steel.

Installation Notes

This tap is installed by licensed machinists or trained tool operators using a tap wrench, tapping head, or CNC rigid tapping cycle. Always ensure the pilot hole is drilled to the correct minor diameter for a 4-40 UNC thread before tapping. Apply appropriate cutting fluid for the workpiece material to extend tool life and reduce heat buildup. Do not reverse-torque or force the tap if resistance is felt — back off to break chips before continuing.