Osg 1657505008 Spiral Flute Pipe Tap 1/8-27 Npt Hss

Product Description

The OSG 1657505008 is a spiral flute pipe tap designed to cut 1/8-27 NPT internal threads in a wide range of materials. Built from high-speed steel with a V-coating finish, it features a 40-degree right-hand helix that drives chips forward and out of the hole during tapping, reducing the risk of chip packing in blind or shallow through-hole applications. The tap measures 4 inches in overall length with a thread length of 0.752 inches and a shank diameter of 0.438 inches. It is used by machinists, pipefitters, and plumbers wherever NPT-threaded pipe connections must be cut directly into workpiece material.

This tap is suited for threading pipe-size holes in carbon steel, alloy steel, stainless steel, cast iron, cast aluminum, titanium, and hardened steel. The 1/8-27 NPT thread form is the standard fitting size used extensively in hydraulic lines, pneumatic circuits, plumbing assemblies, and instrumentation connections. The spiral flute design makes it especially effective in materials that produce stringy chips, where a straight-flute tap would pack and bind. It is sold individually and is intended for use in machine tapping setups as well as hand tapping with a suitable tap wrench.

Key Features

• 1/8-27 NPT thread form for standard pipe-connection applications
• 40-degree right-hand spiral flute geometry evacuates chips ahead of the tap during cutting
• High-speed steel construction with V-coating for extended tool life across a broad material range
• 3-flute design balances cutting load and chip clearance
• Compatible with carbon steel, alloy steel, stainless steel, cast iron, cast aluminum, titanium, and hardened steel
• No coolant-through feature; relies on external cutting fluid application

Compatibility

Designed for use in any machine or hand tapping application requiring a 1/8-27 NPT thread; compatible with standard tap holders and tap wrenches sized for a 0.438-inch shank diameter.

Installation Notes

Spiral flute pipe taps should be installed by a qualified machinist or pipefitter using a properly aligned tap holder or tap wrench. Always apply cutting fluid rated for the workpiece material before and during tapping to reduce heat and tool wear. Secure the workpiece firmly before starting the tap to prevent misalignment, which can break the tool or produce off-axis threads. Verify that the drilled hole diameter matches the correct NPT tap drill size for 1/8-27 threads before beginning the operation.