Osg 1136400 Straight Flute Plug Tap 1-12 Unf Hss

Product Description

The OSG 1136400 is a straight flute plug tap designed for cutting right-hand internal threads to the 1-12 UNF standard. Built from high-speed steel with a bright, uncoated finish, it features 4 flutes and an H4 thread limit, delivering consistent thread geometry in a 3B class of fit. The plug chamfer - typically 3 to 5 threads - makes it suitable for through-hole and moderately deep blind-hole applications. Overall length is 5-1/8 inches with a thread length of 2-1/2 inches. This tap is intended for use by machinists and tool-and-die professionals working in production or maintenance environments.

The 1136400 is rated for tapping into a range of common engineering materials, including aluminum, cast aluminum, cast iron, low-carbon steel, medium-carbon steel, and high-carbon steel. Its straight flute design works best in shorter chipping materials where chip evacuation is not a limiting factor. Typical applications include threading bolt holes, threaded inserts, and fastener bores in structural and mechanical assemblies requiring a 1-12 UNF thread form.

Key Features

• 1-12 UNF thread standard with 3B class of fit for precise thread tolerance control
• H4 thread limit ensures consistent oversize compensation for coated or plated fasteners
• Plug chamfer style accommodates through holes and moderate-depth blind holes
• 4-flute straight design optimized for short-chip materials such as cast iron and carbon steels
• High-speed steel construction provides durability across a broad range of common workpiece materials
• Bright uncoated finish allows direct visual inspection of cutting edge condition

Compatibility

Designed as an OEM-style straight flute tap for 1-12 UNF threaded applications; part of OSG Series 101. Compatible material applications include aluminum, cast aluminum, cast iron, high-carbon steel, low-carbon steel, and medium-carbon steel.

Installation Notes

Installation should be performed by qualified machinists using a properly aligned tapping head, tapping arm, or CNC machine to prevent tap breakage from misalignment. Power down and de-energize all machine tooling before changing or inspecting taps. Use an appropriate cutting fluid or tapping compound for the workpiece material to extend tool life and improve thread finish. Do not force a tap that shows resistance - back off to clear chips before continuing.