Osg 1171300 Straight Flute Tap 3/8-16 Unc Plug Hss

Product Description

The OSG 1171300 is a straight flute tap designed for cutting internal threads in a range of ferrous and non-ferrous materials. Built from high-speed steel (HSS) with a bright, uncoated finish, it cuts a 3/8-16 UNC thread profile to a 3B class of fit with an H3 thread limit. The plug chamfer - typically 3 to 5 threads - makes it suitable for through-hole and most blind-hole applications where starting the thread straight is a priority. Overall length is 2-15/16 inches with a thread length of 1-1/4 inches. Machinists, tool-and-die technicians, and maintenance professionals use this tap in both manual and machine tapping setups.

This tap is used in general-purpose tapping applications across manufacturing, maintenance, repair, and fabrication environments. It is rated for use in aluminum, cast aluminum, cast iron, high-carbon steel, low-carbon steel, and medium-carbon steel. The 3-flute straight flute geometry provides good chip clearance and is well-suited for use with standard tapping fluids in both horizontal and vertical orientations. It fits standard tap handles and machine tap holders sized for the 3/8-inch shank diameter.

Key Features

• 3/8-16 UNC thread form, 3B class of fit, H3 thread limit for consistent tolerance control
• Plug chamfer (3-5 thread lead) for easy thread starting in through-holes and most blind holes
• High-speed steel construction for durability across a wide range of workpiece materials
• 3 straight flutes for efficient chip evacuation during tapping
• Bright, uncoated finish - no coating buildup concerns on close-tolerance threads
• Right-hand thread direction, compatible with standard tap handles and tapping heads

Compatibility

Designed as an OEM-style replacement or standard tooling tap for 3/8-16 UNC thread applications. Compatible with material types including aluminum, cast aluminum, cast iron, high-carbon steel, low-carbon steel, and medium-carbon steel as specified by the manufacturer.

Installation Notes

Install using a properly sized tap handle or machine tapping attachment rated for the shank diameter. Secure the workpiece before tapping and apply appropriate cutting fluid for the workpiece material to reduce heat and extend tap life. Reverse the tap periodically during hand tapping to break chips and prevent binding. Inspect the tap for wear or damage before each use - a dull or chipped tap should not be forced, as it risks breakage inside the workpiece.