Hertel R867171 Extension Tap 3/4-16 Unf 4 Flute Hss

Product Description

The HERTEL R867171 is an extension tap designed for cutting 3/4-16 UNF internal threads in a variety of metalworking applications. Built from high speed steel with a bright, uncoated finish, this tap features a plug chamfer, 4 flutes, and an H3 thread limit for consistent tolerance control. The overall length of 6 inches provides extended reach for deeper or harder-to-access hole locations. A reduced shank diameter of 0.59 inches allows use in standard tap holders. This tool is intended for use by machinists, maintenance technicians, and toolroom professionals working with inch-series unified fine threads.

This extension tap is suited for threading applications where standard-length taps cannot reach the workpiece, such as recessed bores, deep fixtures, or obstructed setups. The 3/4-16 UNF thread form is common in precision mechanical assemblies, fluid fittings, and industrial equipment. The plug chamfer style makes it appropriate for through-holes and blind holes with adequate clearance at the bottom. It is typically used in manual tapping operations or with low-speed tapping equipment, and the Class 3B fit designation makes it appropriate for close-tolerance thread requirements.

Key Features

• 3/4-16 UNF thread size with H3 thread limit for tight tolerance control
• Plug chamfer accommodates through-hole and most blind-hole applications
• 6-inch overall length provides extended reach into recessed or obstructed workpieces
• Reduced shank diameter of 0.59 inches fits standard tap holders
• High speed steel construction offers durability across a range of ferrous and non-ferrous materials
• Bright, uncoated finish suited for general-purpose threading operations

Compatibility

Designed as an OEM-style replacement or direct-use extension tap for applications requiring 3/4-16 UNF Class 3B internal threads with a plug chamfer and H3 limit.

Installation Notes

This tap should be installed and operated by qualified machinists or maintenance technicians familiar with threading tools and tapping procedures. Secure the tap firmly in a compatible tap holder or chuck before use, and ensure the workpiece is properly fixtured and lubricated with an appropriate cutting fluid for the material being tapped. Never force a tap against resistance without backing it off to break chips, as this can cause breakage. Always verify thread tolerance and class of fit requirements before selecting this tool for a given application.