Osg 1400103800 Thread Forming Tap 3-48 Unc Cobalt

Product Description

The OSG 1400103800 is a thread forming tap in the HY-PRO NRT series, designed for cold-forming internal threads rather than cutting them. It produces 3-48 UNC threads with a modified bottoming chamfer of 2 to 2.5 threads, allowing it to tap close to the bottom of a blind hole. Manufactured from cobalt high-speed steel with a bright finish, this tap delivers strength and wear resistance when working in demanding materials. The right-hand thread direction and H3 thread limit make it suitable for achieving a Class 2B fit. Licensed machinists and tooling technicians use this tap in production and maintenance threading operations.

This tap is suited for blind hole threading applications across a range of metallic workpieces. Compatible material applications include alloy steel, aluminum, carbon steel, die steel, hardened steel, and stainless steel. The modified bottoming chamfer is particularly useful in situations where thread engagement must start near the bottom of a drilled hole with minimal runout. It is appropriate for both production shop environments and precision maintenance work requiring close-tolerance UNC threads in small fastener sizes.

Key Features

• Thread forming design cold-forms threads without producing chips, reducing the risk of chip packing in blind holes
• Cobalt high-speed steel construction provides elevated heat and wear resistance over standard HSS taps
• Modified bottoming chamfer with 2 to 2.5 chamfered threads for threading close to the base of blind holes
• H3 thread limit produces a Class 2B fit for standard UNC thread tolerance requirements
• Right-hand thread direction with no coolant-through requirement for straightforward setup
• Bright finish with no additional coating, suited for use with standard tapping fluids

Compatibility

Designed for blind hole threading in alloy steel, aluminum, carbon steel, die steel, hardened steel, and stainless steel workpieces requiring 3-48 UNC internal threads at a Class 2B fit.

Installation Notes

This tap should be installed in a tap holder or tapping chuck that provides proper alignment to avoid tap breakage, particularly important given the small diameter of a No. 3 thread. Always apply an appropriate tapping fluid or cutting oil matched to the workpiece material before starting. Ensure the tap is driven at correct speed and feed for the material being threaded and that the drilling machine or tapping arm is properly aligned to the hole axis. Inspect the tap for wear regularly, as small-diameter cobalt taps are susceptible to breakage if operated in worn condition or under misalignment.