Hertel K008662AS 1-1/4-7 Unc Bottoming Tap 4 Flute Hss

Product Description

The HERTEL K008662AS is a straight flute bottoming tap designed to cut 1-1/4-7 UNC internal threads in through or blind holes where full thread depth to the bottom of a bore is required. Manufactured from high speed steel with a bright uncoated finish, this tap features 4 straight flutes and a bottoming chamfer that minimizes the unthreaded zone at the base of a hole. The H4 thread limit designation indicates an oversize tolerance suited for tapping harder materials or plated applications. Overall length is 5.75 inches. Right-hand thread direction. Class of fit is 3B.

This tap is appropriate for machine shop, maintenance, and toolroom applications involving larger diameter fastener threads in ferrous and non-ferrous materials. The 1-1/4-7 UNC thread form is common in heavy equipment, structural assemblies, and industrial machinery where coarse-pitch threads are specified. The straight flute geometry works well in through-hole applications and in shorter-chipping materials such as cast iron and brass. Licensed machinists, tool and die makers, and maintenance mechanics are the typical end users.

Key Features

• Bottoming chamfer allows threading to within 1-2 pitches of a blind hole bottom
• 4 straight flutes for stability and chip management in short-chipping materials
• H4 thread limit for use in harder materials or where post-plate fit is required
• High speed steel construction provides strength and wear resistance without carbide cost
• Bright uncoated finish for general-purpose tapping without coating-related dimensional offset
• Right-hand cut, Class 3B fit for standard precision internal thread applications

Compatibility

Designed as an OEM-style replacement or direct substitute for 1-1/4-7 UNC bottoming taps used in standard machine tapping operations requiring a 3B class of fit.

Installation Notes

This tap is intended for use by qualified machinists operating drill presses, CNC machining centers, or manual tapping equipment. Ensure the workpiece is securely fixtured and the pilot hole diameter is correct for a 1-1/4-7 UNC thread before beginning the tapping operation. Use an appropriate cutting fluid or tapping compound for the workpiece material to extend tool life and improve thread finish. Do not attempt to back out a tap under power without reversing spindle direction, as this can fracture the tool.