Osg 1400127900 Thread Forming Tap 1/4-28 Unf Bottoming

Product Description

The OSG 1400127900 is a thread forming tap designed for 1/4-28 UNF blind hole threading in a wide range of metals. Unlike cutting taps, this bottoming-style forming tap displaces material rather than cutting it, producing stronger threads with no chips to evacuate. Built from cobalt high-speed steel with a bright finish, it handles demanding applications in alloy steel, stainless steel, hardened steel, carbon steel, die steel, and aluminum. The bottoming chamfer of 1 to 1.5 threads allows threading close to the bottom of a blind hole. Overall length is 2.5 inches with a thread length of 0.594 inches and a tapping depth of 0.933 inches. Thread limit is H5, appropriate for standard tolerance fits on 1/4-28 UNF internal threads.

This tap is suited for machine shops, maintenance operations, and production environments where blind hole threading is required in ferrous and non-ferrous metals. The right-hand thread direction and bottoming chamfer make it a direct choice when threading must reach near the base of a drilled hole. It is sized for use in CNC machining centers, drill presses, and tapping arms. The HY-PRO NRT series from OSG is positioned for forming threads in materials that work well under plastic deformation rather than chip removal, including aluminum and low-to-medium carbon steels as well as tougher alloys.

Key Features

• Thread forming (chipless) design produces stronger threads and eliminates chip evacuation concerns in blind holes
• Bottoming chamfer of 1 to 1.5 threads allows threading close to the bottom of a blind hole
• Cobalt high-speed steel construction supports use in hardened steel and stainless steel applications
• H5 thread limit provides consistent tolerance control for standard 1/4-28 UNF fits
• Bright finish with no coolant-through requirement simplifies setup
• Right-hand thread direction; compatible with standard tapping heads and holders

Compatibility

Designed for blind hole thread forming in alloy steel, aluminum, carbon steel, die steel, hardened steel, and stainless steel. Material application codes P and N confirm suitability across these metal families. Intended for use wherever a 1/4-28 UNF internal thread is required in a blind hole application.

Installation Notes

Thread forming taps require a specific forming tap drill size, which differs from standard tap drill charts used for cut taps — consult OSG or a tooling reference for the correct hole diameter before drilling. Ensure the workpiece is rigidly clamped and the tap is driven with a synchronous tapping head or rigid tapping cycle to prevent thread distortion. Use an appropriate forming tap lubricant for the material being tapped; dry running is not recommended. Power down or de-energize the machine before changing tooling per standard lockout/tagout procedures.