Osg 1400129200 Thread Forming Tap 1/4-28 Unf Plug Cobalt

Product Description

The OSG 1400129200 is a thread forming tap designed for right-hand, through-hole threading in a 1/4-28 UNF configuration. Built from cobalt high-speed steel with a bright finish, this plug chamfer tap is part of the HY-PRO NRT series. It operates without coolant-through capability and carries an H3 thread limit for controlled tolerance fits. At 2.5 inches overall length with a 0.594-inch thread length, it is sized for compact fastening applications. Machinists and tool-and-die professionals use this tap in production and maintenance environments where consistent thread form and material hardness are required.

This tap is suited for threading alloy steel, aluminum, carbon steel, die steel, hardened steel, and stainless steel workpieces. The plug chamfer, with 4 to 4.5 chamfered threads, makes it appropriate for through-hole applications where the tap can pass fully through the material. It is a practical choice for general machining, tool room work, and production tapping where a roll-form thread is preferred over a cut thread to avoid chip generation and improve thread strength.

Key Features

• 1/4-28 UNF right-hand thread form for standard unified fine-thread applications
• Cobalt high-speed steel construction for heat and wear resistance in tough materials
• Plug chamfer with 4 to 4.5 chamfered threads for through-hole entry and threading
• H3 thread limit provides consistent tolerance control for close-fit threaded assemblies
• Thread forming design eliminates chips, reducing tap breakage risk in blind and through holes
• Bright finish with no coating for straightforward application across multiple material types

Compatibility

Designed for through-hole thread forming in alloy steel, aluminum, carbon steel, die steel, hardened steel, and stainless steel with material application codes P and N.

Installation Notes

This tap is installed by machinists using a tapping head, CNC machine, or hand tap wrench sized to the 0.255-inch shank diameter. Power down or lock out the machine spindle before securing or changing tooling. Thread forming taps require a properly sized forming tap drill - not a standard cut tap drill size - to achieve the correct minor diameter and avoid tool breakage. Always apply appropriate tapping fluid for the workpiece material to extend tool life and maintain thread quality.