Hertel K011534AS Straight Flute Tap 1/4-20 Unc 4 Flutes

Product Description

The HERTEL K011534AS is a straight flute plug tap designed for cutting right-hand internal threads in standard UNC applications. Built from high-speed steel (HSS) with a bright/uncoated finish, this tap produces a 1/4-20 UNC thread profile with a 1 inch thread length and an overall length (OAL) of 2.5 inches. The plug chamfer style provides a moderate lead-in, making it suitable for through-hole tapping as well as partially blind holes where starting ease and thread engagement balance are both priorities. The H7 thread limit designation ensures the tap produces threads within the standard tolerance range for general-purpose fastener fit. Four flutes provide efficient chip evacuation and cutting edge support during threading operations.

This tap is intended for use in metal fabrication, maintenance and repair, and production threading work where 1/4-20 UNC threads are required. It is well suited to hand tapping and machine tapping setups in steel, cast iron, aluminum, and similar materials within the capability of HSS tooling. Machinists, pipefitters, millwrights, and general maintenance technicians commonly use this tap size for fastener thread repair and new thread creation in light to medium-duty assemblies.

Key Features

• 1/4-20 UNC thread profile with right-hand thread direction
• Plug chamfer for versatile use in through-hole and semi-blind applications
• 4-flute geometry for balanced cutting and chip clearance
• High-speed steel construction for durability across a range of metallic workpiece materials
• H7 thread limit for standard general-purpose thread tolerance
• Bright/uncoated finish — no coating buildup affecting tap dimensions

Compatibility

Designed as a standard replacement or production tap for any application requiring a 1/4-20 UNC straight flute plug tap with H7 thread limit in HSS.

Installation Notes

Secure the workpiece before tapping and use appropriate cutting fluid or tapping oil to extend tool life and improve thread finish. Ensure the tap is started perpendicular to the workpiece surface to avoid cross-threading or tap breakage. For machine tapping, verify spindle speed and feed rate are appropriate for the workpiece material and tap diameter. Always use a proper tap wrench or collet chuck sized for the shank diameter of 0.255 inches.