Reiff Nestor 45839 Extension Tap 1-8 Unc 4 Flute Hss

Product Description

The REIFF NESTOR 45839 is a straight-point plug chamfer extension tap designed for cutting 1-8 UNC internal threads in applications where standard-length taps cannot reach. Built from high-speed steel (HSS) with a bright, uncoated finish, this tap delivers reliable performance in ferrous and non-ferrous materials. At 6 inches overall length with a 0.80-inch reduced shank diameter, it provides the reach needed for deep-hole tapping while maintaining compatibility with standard tap holders. The H4 thread limit and Class 3B fit make it suitable for applications requiring close-tolerance threaded connections. Four right-hand flutes provide efficient chip evacuation during through-hole and open-setup tapping operations.

This extension tap is used in machining, maintenance, and repair operations where standard-reach taps fall short. The plug chamfer (3-5 thread lead) makes it well suited for through-hole tapping or for continuing threads started by a taper tap. Typical applications include threading deep bores in structural components, machine frames, piping flanges, and fabricated assemblies. It is commonly used by machinists, millwrights, pipefitters, and maintenance technicians working on equipment where fastener access is restricted or recessed.

Key Features

• 1-8 UNC thread size with H4 thread limit for consistent, close-tolerance fit
• 6-inch overall length provides extended reach for deep or recessed tapping
• Plug chamfer (3-5 thread lead) suits through-hole and open-bore applications
• High-speed steel construction handles a wide range of workpiece materials
• Reduced shank at 0.80 inches allows use with standard tap holders and extension drivers
• Right-hand, 4-flute straight design promotes chip clearance in open setups

Compatibility

Designed as an OEM-style replacement or direct-use extension tap for 1-8 UNC tapping applications requiring a 6-inch overall length with a reduced shank and Class 3B fit tolerance.

Installation Notes

Extension taps are typically installed by machinists or maintenance technicians using a tap handle, tap wrench, or appropriate machine holder rated for the shank diameter. Always secure the workpiece and ensure proper alignment before beginning the tapping operation to prevent tap breakage. Apply cutting fluid appropriate to the workpiece material, and back off periodically to break and clear chips. Never force a tap against resistance - back out and clear chips before continuing.