Osg 1400128300 Thread Forming Tap 1/4-28 Unf Cobalt

Product Description

The OSG 1400128300 is a thread forming tap in the HY-PRO NRT series, designed for cold-forming internal threads without cutting. Unlike cutting taps, thread forming taps displace material rather than remove it, producing stronger threads with no chips to clear. This tap is configured for 1/4-28 UNF right-hand threads, built from cobalt high-speed steel with a bright finish, and features a modified bottoming chamfer of 2 to 2.5 threads. The H3 thread limit controls pitch diameter tolerance for consistent fit. Overall length is 2.5 inches, with a thread length of 0.594 inches and a tapping depth capacity of 0.933 inches. It is installed by machinists and tooling technicians in production and job shop environments.

This tap is suited for blind hole threading applications across a range of materials including alloy steel, aluminum, carbon steel, die steel, hardened steel, and stainless steel. The modified bottoming chamfer allows threading close to the bottom of a blind hole while still providing enough lead to start cleanly. The cobalt construction handles the elevated heat and work-hardening common in stainless and alloy steels. It is a practical choice for both manual tapping and machine tapping setups where chip clearance is a concern and thread strength is critical.

Key Features

• Thread forming design displaces material rather than cutting, producing stronger threads with no chip generation
• Modified bottoming chamfer (2 to 2.5P) enables threading close to the bottom of blind holes
• Cobalt high-speed steel construction withstands heat and abrasion in tough materials including hardened and stainless steels
• H3 thread limit ensures controlled pitch diameter tolerance for consistent thread fit
• Right-hand, 1/4-28 UNF configuration for fine-thread applications requiring close tolerances
• Bright finish with no coolant-through requirement, suitable for standard lubricated tapping operations

Compatibility

Designed for blind hole thread forming in alloy steel, aluminum, carbon steel, die steel, hardened steel, and stainless steel workpieces. Material application codes P and N confirm suitability for these material groups.

Installation Notes

Thread forming taps require a properly sized forming tap drill — do not use standard cutting tap drill sizes, as the hole diameter is critical to achieving correct thread form and avoiding tap breakage. Apply tapping fluid or cutting oil appropriate for the workpiece material before and during tapping. Secure the workpiece and ensure the tap is properly aligned before engaging to prevent cross-threading or tap breakage. Tapping machines or torque-controlled drivers are recommended for consistent results, especially in hardened materials.