Osg 1400125708 Thread Forming Tap 1/4-20 Unc Bottoming Ticn

Product Description

The OSG 1400125708 is a thread forming tap in the HY-PRO NRT series, designed for cold-forming internal threads in blind holes without cutting or producing chips. Sized for 1/4-20 UNC right-hand threads, it features a bottoming chamfer with 1 to 1.5 thread chamfer length, allowing threading close to the bottom of a blind hole. Manufactured from cobalt high-speed steel and finished with a TiCN coating, the tap delivers improved hardness and heat resistance compared to standard M2 tooling. Overall length is 2.5 inches, with a thread length of 0.594 inches and a shank diameter of 0.255 inches. The H6 thread limit provides a controlled fit tolerance suitable for general industrial fastener applications. Machinists and tool-and-die technicians use this tap in CNC tapping operations and manual tapping where chip evacuation in blind holes is a concern.

This tap is suited for blind hole threading in a range of metallic workpiece materials, including alloy steel, carbon steel, die steel, hardened steel, stainless steel, and aluminum. The thread forming process displaces material rather than cutting it, resulting in stronger thread forms with no chips to clear from the hole. It is a practical choice for production environments that require consistent thread quality in ductile and semi-ductile metals. The bottoming chamfer design makes it especially useful when thread engagement must begin very close to the bottom of a drilled hole with minimal runout distance.

Key Features

• 1/4-20 UNC right-hand thread, bottoming chamfer with 1 to 1.5 chamfered threads
• Cobalt high-speed steel construction for elevated heat and wear resistance
• TiCN coating extends tool life in abrasive and high-hardness materials
• Thread forming design eliminates chips, ideal for blind hole applications
• H6 thread limit for consistent, controlled thread tolerance
• Tapping depth of 0.933 inches supports deeper thread engagement in blind holes

Compatibility

Designed for blind hole thread forming in alloy steel, carbon steel, die steel, hardened steel, stainless steel, and aluminum workpieces. Compatible with standard 1/4-inch tap holders and CNC tapping chucks with a 0.255-inch shank diameter and 0.191-inch square drive.

Installation Notes

Thread forming taps require proper hole preparation — the pilot hole diameter for a forming tap is larger than that used for a cutting tap and must be sized to the recommended forming drill chart for 1/4-20 UNC. Apply appropriate tapping fluid or cutting oil for the workpiece material before tapping. Ensure the tap is driven at the correct RPM and feed rate for the material and machine setup; excessive speed or misalignment can strip the formed thread or break the tap. This tap does not have coolant-through capability, so external lubrication is required.