Osg 1400127905 Thread Forming Tap 1/4-28 Unf Bottoming

Product Description

The OSG 1400127905 is a thread forming tap in the HY-PRO NRT series, designed for cold-forming internal threads without cutting or producing chips. Built from cobalt high-speed steel with a titanium nitride (TiN) coating, this tap delivers high wear resistance and extended tool life in demanding production environments. It produces 1/4-28 UNF right-hand threads and features a bottoming chamfer with 1 to 1.5 chamfered threads, allowing thread forming close to the bottom of a blind hole. Overall length is 2.5 inches with a thread length of 0.594 inches and a shank diameter of 0.255 inches. Installation requires a properly sized forming tap drill — not a standard tap drill — to achieve the correct pre-hole diameter for cold-forming.

This tap is suited for blind hole threading applications across a broad range of metallic workpiece materials. It performs in alloy steel, carbon steel, die steel, hardened steel, aluminum, and stainless steel, making it a versatile choice for machine shops, maintenance facilities, and production toolrooms. The H5 thread limit designation ensures dimensional control appropriate for standard UNF fit classes. The bottoming chamfer style makes it especially useful in applications where threads must extend to near the bottom of a drilled hole with minimal thread runout.

Key Features

• Thread forming (chipless) design eliminates chip packing in blind holes
• Cobalt high-speed steel construction for heat and wear resistance
• TiN coating reduces friction and extends coating life in high-cycle applications
• Bottoming chamfer with 1 to 1.5 chamfered threads for near-bottom thread forming
• H5 thread limit for consistent UNF dimensional tolerance control
• Right-hand thread direction, 1/4-28 UNF specification

Compatibility

Designed for blind hole thread forming in alloy steel, carbon steel, die steel, hardened steel, aluminum, and stainless steel workpieces. Compatible with standard 1/4-28 UNF toolholding setups accepting a 0.255-inch shank diameter. Material application codes P and N apply.

Installation Notes

Thread forming taps require a forming tap drill — not a conventional tap drill — sized for the specific material and thread form; consult the tap manufacturer drill size chart before drilling. Power down all equipment before tap changes and secure workpieces firmly to prevent movement during tapping. Use appropriate tapping fluid or cutting oil matched to the workpiece material to reduce galling, particularly in stainless steel. Follow applicable shop safety procedures and machine tool manufacturer guidelines for speed and feed settings.