Osg 1250502 Spiral Flute Pipe Tap 1/8-27 Npt Hss

Product Description

The OSG 1250502 is a spiral flute pipe tap designed to cut 1/8-27 NPT internal threads in pipe fittings, manifolds, and threaded ports. Built from high-speed steel with an elektraLUBE finish, it runs with a 15-degree right-hand helix and 4 flutes to efficiently evacuate chips from the cut zone. The bottoming chamfer geometry lets the tap thread close to the bottom of a blind hole, making it suitable for applications where thread engagement depth is critical. This tap is a standard tool for machinists, pipefitters, and maintenance technicians cutting NPT threads in steel, cast iron, aluminum, and similar materials.

The OSG 1250502 is used in applications requiring tapered pipe threads conforming to the NPT standard. It is suited for production tapping, repair work, and field maintenance on hydraulic ports, pneumatic fittings, and pipe assemblies. The bottoming chamfer design makes it particularly useful in shallow or blind-hole conditions where a plug or taper chamfer tap cannot reach full thread depth. It fits standard tap holders and machines used in light manufacturing and MRO environments.

Key Features

• 1/8-27 NPT thread form for standard tapered pipe thread connections
• 15-degree right-hand spiral helix promotes chip evacuation during cutting
• 4-flute design provides a balance of cutting efficiency and tool rigidity
• Bottoming chamfer allows threading close to the base of a blind hole
• High-speed steel construction offers toughness across a broad range of workpiece materials
• elektraLUBE finish reduces friction and extends tool life in dry or minimal-lubrication tapping

Compatibility

Designed for use in standard tap holders, T-handle wrenches, and CNC tapping heads that accept a 0.4375-inch shank diameter with a 0.328-inch square drive. Suitable for cutting 1/8-27 NPT threads in metal workpieces across general manufacturing, plumbing, hydraulic, and pneumatic applications.

Installation Notes

A licensed machinist or qualified technician should select the correct tap drill size for 1/8-27 NPT threads before use. Secure the workpiece fully and ensure the tap is aligned perpendicular to the drilled hole to prevent tap breakage or thread misalignment. Apply appropriate cutting fluid unless the elektraLUBE finish is used in a dry or near-dry tapping process. Back the tap out periodically to clear chips when tapping deeper holes.