Osg 1121900 Straight Flute Plug Tap 7/16-14 Unc Hss

Product Description

The OSG 1121900 is a straight flute plug tap designed for cutting internal 7/16-14 UNC right-hand threads in a range of ferrous and non-ferrous metals. Built from high-speed steel with a bright uncoated finish, this tap delivers consistent thread quality in production and maintenance settings. It features 4 flutes and a plug chamfer, which provides a moderate lead-in that works well for through-holes and blind holes with adequate chip clearance. Overall length is 3-5/32 inches, with a thread length of 1-7/16 inches. Thread limit is H3, suitable for standard tolerance class 2B threaded holes. Licensed machinists, tool and die makers, and maintenance technicians are the primary users.

This tap is suited for threading operations in general manufacturing, job shop, and industrial maintenance environments. The straight flute geometry is well matched to short-chipping materials. Compatible material applications include aluminum, cast aluminum, cast iron, high-carbon steel, low-carbon steel, and medium-carbon steel. The plug chamfer style makes it a versatile choice for both through-hole and accessible blind-hole applications where a starting taper is not required.

Key Features

• 7/16-14 UNC thread form with H3 thread limit for standard 2B fit tolerance
• 4-flute straight flute design optimized for short-chipping materials
• Plug chamfer provides moderate lead-in for through-holes and open blind holes
• High-speed steel construction for durability across a range of work materials
• Bright uncoated finish - no coating buildup to affect thread dimensions
• Right-hand thread direction, no coolant-through requirement

Compatibility

Designed as a standard replacement or production straight flute plug tap for 7/16-14 UNC threading operations in aluminum, cast aluminum, cast iron, high-carbon steel, low-carbon steel, and medium-carbon steel workpieces.

Installation Notes

Secure the workpiece firmly before tapping and ensure the tap is properly aligned with the pilot hole to avoid bell-mouthing or tap breakage. Use an appropriate tapping fluid or cutting oil matched to the work material - dry tapping is not recommended for steel applications. Back the tap out periodically to clear chips when working in deeper holes. This tap does not support coolant-through delivery, so external lubrication is required.