Hertel 015974AS Extension Pipe Tap 1/4-18 Nptf 5 Flute Hss

Product Description

The HERTEL 015974AS is a 1/4-18 NPTF extension pipe tap ground from high speed steel and finished bright. It is designed to cut tapered pipe threads in ferrous and non-ferrous materials where a standard-length tap cannot reach the work. The five-flute geometry distributes cutting load evenly and clears chips efficiently in through and blind applications. With a 6-inch overall length and a 0.5625-inch shank diameter, this tap gives machinists and pipefitters the reach needed in recessed bores, deep castings, and fabricated assemblies. The NPTF thread form produces a pressure-tight, dryseal fit without sealant tape when properly cut and gauged.

This tap is suited for threading pipe ports in hydraulic manifolds, pneumatic fittings, fluid system housings, and plumbing assemblies where access depth exceeds what a standard pipe tap can accommodate. It is commonly used in maintenance, repair, and original equipment manufacturing environments. Machinists, pipefitters, and HVAC technicians working with ferrous castings, steel plate, brass fittings, and similar materials will find this extension tap appropriate for 1/4-inch pipe thread applications in tight or deep locations.

Key Features

• 1/4-18 NPTF thread form produces dryseal tapered pipe threads for pressure-tight connections
• 5-flute design distributes cutting forces and improves chip evacuation
• 6-inch overall length provides extended reach into deep or recessed bores
• High speed steel construction offers toughness and wear resistance across a range of workpiece materials
• Bright finish with no coating, suitable for use with cutting oils and standard tapping fluids
• Interrupted thread profile reduces torque and friction during the cut

Compatibility

Designed as an extension-style NPTF pipe tap for use in standard tapping chucks, tap wrenches, and machine spindles accepting a 0.5625-inch round shank with a 0.4210-inch square drive.

Installation Notes

A licensed machinist or pipefitter should perform tapping operations; always secure the workpiece fully before engaging the tap. Apply a suitable cutting oil or tapping fluid throughout the operation to reduce heat and extend tool life. Back the tap out periodically to break and clear chips, especially in blind holes. Use a calibrated NPTF plug gauge after threading to verify the dryseal fit before assembly.