Hertel K008686AS Straight Flute Tap 1-1/2-6 Unc Bottoming Hss

Product Description

The HERTEL K008686AS is a straight flute bottoming tap designed to cut 1-1/2-6 UNC internal threads in through-holes and blind holes where threads must extend close to the bottom. Ground from high speed steel with a bright, uncoated finish, it runs 4 flutes and carries a 3B class of fit tolerance for standard fastener applications. The H4 thread limit provides controlled oversize stock for plating allowance or tight-tolerance thread fits. Overall length is 6.375 inches, and the tap uses a right-hand thread direction. Machinists and tool-and-die tradespeople use this size for heavy structural, industrial, and mechanical assembly applications requiring large-diameter threaded holes.

This tap is suited for tapping operations in ferrous and non-ferrous materials on manual lathes, drill presses, CNC machining centers, and knee mills. The bottoming chamfer - typically 1 to 2 threads - allows threading to within one or two thread pitches of a blind hole bottom, making it appropriate for final-pass tapping after a taper or plug tap has been used to start the thread. Applications include manufacturing fixtures, heavy equipment components, pipe flanges, and structural steel assemblies where 1-1/2-6 UNC threads are specified.

Key Features

• Bottoming chamfer for threading close to the bottom of blind holes
• 4 straight flutes for chip control in a range of materials
• High speed steel construction for durability in production tapping
• Bright, uncoated finish - no additional coating buildup on thread form
• H4 thread limit for controlled oversize fit, accommodating plating or tight tolerance requirements
• 3B class of fit for standard general-purpose UNC thread engagement
• Right-hand thread direction, 1-1/2-6 UNC form

Compatibility

Designed as a standard straight flute bottoming tap for 1-1/2-6 UNC threaded hole applications. Fits standard tap holders and floating tap collets accepting 1-1/2 inch shank taps. Verify shank dimensions and drive configuration against your tap holder before installation.

Installation Notes

This tap should be installed by a machinist or qualified trades professional familiar with large-diameter tapping operations. Ensure the workpiece is securely fixtured and the spindle or tapping head is properly aligned before engaging the tap to prevent tap breakage or thread damage. Always use cutting fluid appropriate for the workpiece material. When tapping blind holes, use a taper or plug tap first to start the thread before finishing with this bottoming tap.