Osg 1137100 Straight Flute Tap 1-1/8-7 Unc Hss

Product Description

The OSG 1137100 is a straight flute plug tap designed for cutting internal right-hand threads to the 1-1/8-7 UNC standard. Built from high-speed steel with a bright uncoated finish, it delivers consistent thread form in a wide range of ferrous and non-ferrous materials. The plug chamfer - typically 3 to 5 threads - allows the tap to start easily and is well suited for through-hole applications. With 4 flutes and an H4 thread limit, this tap holds close tolerances and meets a 3B class of fit. Machinists, tool-and-die technicians, and maintenance professionals use it for production and repair threading operations on manual machines, CNC tapping arms, and drill presses.

The OSG 1137100 Series 101 tap is suited for threading aluminum, cast aluminum, cast iron, low-carbon steel, medium-carbon steel, and high-carbon steel. At a 1-1/8-7 UNC thread size, it is commonly used in heavy equipment, structural fabrication, die sets, and industrial maintenance applications where a coarse-pitch unified thread is required. The 5-7/16 inch overall length provides clearance for standard tap holders and machine spindles. It is sold as a single tap per package.

Key Features

• 1-1/8-7 UNC thread form with 3B class of fit and H4 thread limit for precise tolerance control
• Plug chamfer (3 to 5 lead threads) for easy starting in through-hole applications
• 4-flute design provides rigidity and chip control in a broad range of machinable materials
• High-speed steel construction offers good toughness and wear resistance in general-purpose threading
• Bright uncoated finish - no coating buildup to affect thread tolerance
• Right-hand thread direction; compatible with standard tap holders and tapping attachments

Compatibility

Designed for use in aluminum, cast aluminum, cast iron, low-carbon steel, medium-carbon steel, and high-carbon steel workpieces. Fits standard tap holders and collets sized for a 0.896 inch shank diameter. Suitable for manual and machine tapping operations requiring a 1-1/8-7 UNC internal thread.

Installation Notes

This tap is installed and operated by a machinist or maintenance technician using a tap wrench, tapping arm, or CNC spindle set to the correct tapping speed and feed for the workpiece material. Always ensure the workpiece is securely fixtured and the tap is properly aligned with the pilot hole before engagement. Use an appropriate cutting fluid for the material being tapped to extend tool life and improve finish. Inspect the tap for wear or chipping before each use - a damaged tap can seize and break in the hole.