Hertel K008428AS Hand Tap 3/8-16 Unc Taper 4-flute Hss

Product Description

The HERTEL K008428AS is a 3/8-16 UNC straight-flute hand tap ground from high speed steel with a bright uncoated finish. It cuts right-hand internal threads in a taper chamfer configuration, making it the first tap in a standard tap set sequence for starting threads in through-holes or initiating cuts in blind holes. With four flutes and an H1 thread limit, this tap holds close tolerances suitable for general-purpose threading in ferrous and non-ferrous materials. Overall length is 2-15/16 inches with a 1-1/4 inch thread length and a shank diameter of 0.3810 inches. Licensed machinists, maintenance mechanics, pipefitters, and tool-room technicians are the typical users.

This tap is suited for hand tapping operations on the bench or in a tapping fixture where controlled torque and alignment can be maintained. The 3/8-16 UNC thread form is one of the most common fastener sizes in industrial, mechanical, and structural assemblies. Typical applications include threading bolt holes in steel plate, cast iron, aluminum, and similar materials where a standard unified coarse thread is specified. The taper chamfer distributes cutting load across the first 8 to 10 threads, reducing the risk of tap breakage during entry.

Key Features

• 3/8-16 UNC right-hand thread form for standard unified coarse fastener applications
• Taper chamfer distributes cutting load over the leading threads for easier thread starting
• H1 thread limit for close-tolerance general-purpose threading
• Four straight flutes for chip clearance in through-hole and moderate-depth blind-hole applications
• Bright uncoated high speed steel construction compatible with a wide range of cutting fluids
• 0.3810 inch shank diameter fits standard tap wrenches and tapping fixtures

Compatibility

Designed as a standard hand tap for use in any tap wrench, T-handle, or tapping fixture that accepts a 0.3810 inch shank diameter. Cuts 3/8-16 UNC threads per ASME B1.1 standards.

Installation Notes

Hand tapping should be performed by a qualified machinist or mechanic using a properly sized tap wrench to maintain alignment. Always apply a suitable cutting fluid for the workpiece material to extend tap life and improve thread quality. Back off the tap a half turn periodically to break chips and prevent binding. Never force a tap that has seized in the hole, as high speed steel taps are brittle and will fracture under torsional overload.