Osg 1600107 Straight Flute Tap 1/4-20 Unc Plug Hss

Product Description

The OSG 1600107 is a straight flute plug tap designed for cutting 1/4-20 UNC internal threads in a range of ferrous and non-ferrous workpiece materials. Built from high-speed steel with a nitride/oxide dual coating, it delivers improved wear resistance and reduced friction during tapping operations. The plug chamfer (3-5 threads) provides a gradual thread lead-in, making this tap well suited for through-hole applications. With 4 flutes and an H3 thread limit, it maintains dimensional accuracy within standard 3B class of fit tolerances. Overall length is 2.5 inches with a thread length of approximately 0.756 inches. This tap is installed by machinists, maintenance technicians, and tool and die professionals.

This tap is intended for use in aluminum and cast iron workpiece materials. The straight flute geometry works best in through-hole tapping scenarios where chip evacuation is managed by the operator or coolant flow. It is suited for both manual hand-tapping operations and light-duty machine tapping setups in production and maintenance environments. The 1/4-20 UNC thread form is one of the most common fastener threads in North American manufacturing and repair applications, making this tap a frequent choice for general-purpose thread creation and repair.

Key Features

• 1/4-20 UNC thread form with 4 straight flutes and plug chamfer lead-in
• H3 thread limit for consistent 3B class of fit tolerances
• High-speed steel construction for durability across common workpiece materials
• Nitride/oxide coating reduces friction and improves tool life
• Right-hand thread direction; suitable for standard tapping chucks and tap wrenches
• Rated for aluminum and cast iron applications

Compatibility

Designed for through-hole tapping in aluminum and cast iron workpieces requiring 1/4-20 UNC, 3B class of fit internal threads. Part of OSG Series 101C straight flute tap line.

Installation Notes

Tapping operations should be performed with the workpiece securely fixtured and all rotating equipment properly guarded per applicable shop safety standards. Use appropriate cutting fluid for the workpiece material — sulfur-based oils for cast iron and water-soluble or light petroleum fluids for aluminum. Ensure tap alignment is perpendicular to the workpiece surface before engagement to avoid tap breakage. Reverse the tap periodically during hand tapping to break chips and prevent binding.