Osg 2885700 Spiral Point Tap 1/4-28 Unf Hss Bright

Product Description

The OSG 2885700 is a spiral point plug tap designed for threading 1/4-28 UNF internal threads in through-hole applications. The spiral point geometry pushes chips forward ahead of the cutting zone, making it well suited for production threading in materials such as aluminum, cast aluminum, low-carbon steel, and medium-carbon steel. Manufactured from high-speed steel with a bright finish, the tap holds an H3 thread limit and a 2B class of fit, which meets standard tolerance requirements for most fastener and assembly applications. The 3-flute design provides a balance of chip clearance and tool rigidity across the thread-cutting process.

This tap is used in machine shop, maintenance, and production environments where 1/4-28 UNF through-hole threading is required. It is suitable for use in CNC machining centers, drill presses, and tapping machines. The plug chamfer entry — typically 3 to 5 thread lead-in — makes it appropriate for through-holes where the full thread does not need to start at the very top of the bore. It is commonly installed by machinists, toolroom technicians, and maintenance professionals performing metalwork on aluminum and steel components.

Key Features

• Spiral point geometry pushes chips forward, reducing recutting in through-hole threading
• High-speed steel construction provides durability across aluminum and low-to-medium-carbon steel applications
• Plug chamfer entry for standard through-hole threading operations
• H3 thread limit with 2B class of fit for general-purpose fastener thread tolerances
• Right-hand thread direction, compatible with standard tapping equipment
• Bright finish with no coolant-through requirement, suitable for conventional cutting fluid application

Compatibility

Designed for threading 1/4-28 UNF through-holes in aluminum, cast aluminum, low-carbon steel, and medium-carbon steel workpieces. Compatible with standard tap holders and collet chucks sized for a 0.255-inch shank diameter.

Installation Notes

This tap should be installed and operated by qualified machinists or toolroom technicians familiar with tapping speeds and feeds for the target material. Always secure the workpiece and ensure the tap is properly aligned with the pre-drilled pilot hole before engaging the cutting cycle. Use an appropriate cutting fluid or tapping compound for the workpiece material to extend tool life and improve thread quality. Remove the tap carefully by reversing rotation to avoid breakage, particularly in harder steel materials.