Osg 1400125605 Thread Forming Tap 1/4-20 Unc Bottoming Cobalt

Product Description

The OSG 1400125605 is a bottoming-style thread forming tap in the HY-PRO NRT series, designed for cold-forming internal threads in blind holes without cutting chips. Built from cobalt high-speed steel with a titanium nitride (TiN) coating, this tap displaces material rather than removing it, producing stronger threads with improved surface finish. The 1/4-20 UNC configuration covers a widely used fastener size across general fabrication and mechanical assembly. With an overall length of 2.5 inches and a thread length of 0.594 inches, it fits standard tap holders and machine spindles used in production and maintenance environments. The H5 thread limit suits close-tolerance work.

This tap is suited for threading blind holes in alloy steel, carbon steel, aluminum, die steel, hardened steel, and stainless steel. The bottoming chamfer with 1 to 1.5 chamfered threads allows threading close to the bottom of a hole, making it the correct choice when full thread depth is required in short, closed-end bores. It is commonly used in machine shops, manufacturing plants, and maintenance facilities where a right-hand, 1/4-20 UNC internal thread is needed in production or repair operations.

Key Features

• Bottoming chamfer (1-1.5P) for threading to the bottom of blind holes
• Cobalt HSS construction for improved heat and wear resistance in tough alloys
• TiN coating reduces friction and extends tool life across multiple materials
• Thread forming (chipless) design eliminates chip evacuation concerns in blind holes
• H5 thread limit for close-tolerance 1/4-20 UNC threads
• Right-hand thread direction compatible with standard tapping equipment

Compatibility

Designed for use in alloy steel, aluminum, carbon steel, die steel, hardened steel, and stainless steel workpieces requiring blind hole threading. Compatible with standard 1/4-inch tap holders and CNC or manual tapping equipment configured for 1/4-20 UNC right-hand threads.

Installation Notes

Thread forming taps require a larger pilot hole diameter than cutting taps — consult the appropriate forming tap drill chart for the correct hole size before tapping. Use cutting or tapping fluid appropriate for the workpiece material to reduce heat and extend tap life. Ensure the tap is properly aligned with the hole axis before engagement to avoid bell-mouthing or thread distortion. Machine spindle speed should be set per the tap manufacturer recommendations for the specific workpiece material.