Osg 2854801 Spiral Point Tap 1/4-20 Unc 3 Flute Plug

Product Description

The OSG 2854801 is a spiral point plug tap designed for through-hole threading in a wide range of ferrous and non-ferrous metals. It cuts a 1/4-20 UNC right-hand thread using a 3-flute spiral point geometry that pushes chips forward ahead of the cut, reducing chip clogging in through-hole applications. The tap is manufactured from vanadium-enriched high-speed steel (HSS-E) for improved wear resistance and toughness at elevated cutting temperatures. A steam oxide finish is applied to reduce friction, resist galling, and extend tool life in production environments. Overall length is 2.5 inches with a thread length of 0.594 inches and a shank diameter of 0.255 inches. Thread limit is H7, indicating a controlled oversize tolerance suitable for standard UNC fits.

This tap is suited for threading through-holes in materials including aluminum, low-carbon steel, medium-carbon steel, high-carbon steel, alloy steel, die steel, stainless steel, cast iron, and hardened steel. The plug chamfer style provides a gradual lead-in - typically 3 to 5 threads - making it well suited for through-hole work where the tap can pass fully through the material. It is used in manual tapping, CNC machining centers, and drill press setups wherever a standard 1/4-20 UNC thread is required. Coolant-through is not supported on this tap.

Key Features

• Spiral point geometry pushes chips forward, reducing clogging in through-hole applications
• Vanadium high-speed steel (HSS-E) construction for improved toughness and wear resistance
• Steam oxide coating reduces friction and helps extend tool life
• H7 thread limit with oversize designation for accurate UNC fit control
• Right-hand cut, 3-flute design compatible with standard tapping chucks and holders
• Compatible with a broad range of materials including stainless steel, cast iron, and alloy steel

Compatibility

Designed for through-hole tapping applications requiring a 1/4-20 UNC thread. Compatible with aluminum, hardened steel, stainless steel, high-carbon steel, low-carbon steel, medium-carbon steel, alloy steel, die steel, and cast iron as stated by the manufacturer. Part of OSG Series 280.

Installation Notes

Tapping operations should be performed by a machinist or qualified tooling operator familiar with cutting tool feeds, speeds, and tap breakage risk. Always secure the workpiece and use appropriate tapping fluid or cutting oil for the material being threaded. Ensure the spindle or tapping chuck is aligned perpendicular to the work surface to avoid tap deflection and thread quality issues. Inspect the tap for wear or chipping before each use, as a damaged tap can destroy the workpiece thread.