Osg 1225402 Spiral Point Tap 1/4-28 Unf Plug Hss

Product Description

The OSG 1225402 is a spiral point plug tap designed for threading 1/4-28 UNF internal threads in production and maintenance machining applications. Manufactured from high-speed steel (HSS) with an elektraLUBE coating, it features a 2-flute spiral point geometry that pushes chips ahead of the cutting action to prevent chip packing in through-hole applications. The plug chamfer provides a gradual entry into the workpiece, making it well suited for both hand tapping and machine tapping operations. The H2 thread limit controls the tolerance of the finished thread. Thread length is 1 inch with right-hand cutting direction.

This tap is suited for through-hole threading operations across a broad range of materials including aluminum, cast aluminum, cast iron, low-carbon steel, medium-carbon steel, high-carbon steel, and hardened steel. It fits standard production environments such as job shops, maintenance and repair operations, and manufacturing lines where consistent UNF thread quality is required. The spiral point design makes it most effective in through-hole applications where chips can exit ahead of the tap rather than packing in a blind bore.

Key Features

• 1/4-28 UNF thread size with H2 thread limit for controlled tolerance
• Spiral point geometry pushes chips forward, reducing chip packing in through-hole applications
• High-speed steel construction provides durability across a wide range of workpiece materials
• elektraLUBE coating reduces friction and improves tool life in dry or near-dry machining conditions
• Plug chamfer allows gradual thread engagement, compatible with hand and machine tapping
• Right-hand cutting direction, 2 flutes, Series 105

Compatibility

Designed for threading 1/4-28 UNF through holes in aluminum, cast aluminum, cast iron, low-carbon steel, medium-carbon steel, high-carbon steel, and hardened steel workpieces. Not recommended for blind-hole applications where chip evacuation is limited.

Installation Notes

Machinists and tool and die technicians should secure the workpiece firmly before tapping and ensure the tap is aligned perpendicular to the hole to prevent thread damage or tap breakage. Power down or disengage the machine spindle before manually loading or inspecting the tap. Use appropriate cutting fluid or confirm the elektraLUBE coating meets the lubrication requirements of the material being tapped. Tap drill size selection should follow standard UNF tap drill charts for 1/4-28 threads to achieve the desired thread engagement percentage.