Milwaukee Tool 49-57-5191 Straight Flute Tap 1/4-18 Npt

Product Description

The MILWAUKEE TOOL 49-57-5191 is a straight flute tap designed to cut 1/4-18 NPT internal pipe threads in a range of metals and rigid materials. The taper chamfer on the leading end progressively engages the workpiece, distributing cutting load across several threads for controlled thread formation. With 4 flutes and a right-hand thread direction, this tap suits hand tapping and machine tapping applications. A black oxide finish reduces friction and provides mild corrosion resistance during use and storage. Overall length is 2.25 inches, and the thread length is 0.375 inches. Machinists, pipefitters, and plumbers reach for this tool when threading pipe-size holes for NPT fittings in fabrication and service work.

This tap is used to cut 1/4-18 NPT threads, the standard pipe thread size found throughout plumbing, HVAC, and industrial piping systems. The 2B class of fit is standard for most NPT threaded connections, providing reliable engagement with compatible NPT fittings and couplings. Typical applications include threading holes in manifolds, fittings, brackets, and equipment housings where 1/4-inch pipe ports are required. It is appropriate for use on steel, cast iron, aluminum, and similar materials when the correct cutting fluid is applied.

Key Features

• 1/4-18 NPT thread size for standard pipe thread applications
• 4-flute straight flute geometry for hand and machine tapping
• Taper chamfer distributes cutting load for controlled thread entry
• 2B class of fit for standard NPT connection tolerances
• High-carbon steel construction for thread-cutting durability
• Black oxide finish reduces friction and provides corrosion resistance

Compatibility

Designed as a standard 1/4-18 NPT straight flute tap suitable for use with compatible tap handles, T-handles, and tapping chucks that accept the tap shank size.

Installation Notes

This tap is installed and operated by a machinist, pipefitter, or qualified tradesperson using a tap wrench or machine tapping setup. Always use an appropriate cutting fluid for the workpiece material to extend tap life and improve thread quality. Secure the workpiece firmly before tapping and align the tap perpendicular to the drilled hole to avoid tap breakage. Follow applicable shop safety practices and wear eye protection during all tapping operations.