Osg 1400105300 Thread Forming Tap 4-40 Unc Cobalt

Product Description

The OSG 1400105300 is a thread forming tap designed for 4-40 UNC applications, part of the HY-PRO NRT series. Unlike cutting taps, this tool cold-forms threads by displacing material rather than removing it, producing stronger threads with better surface finish. Built from cobalt high-speed steel with a bright finish, it handles demanding materials including hardened steel and stainless steel. The modified bottoming chamfer with 2 to 2.5 chamfered threads allows threading close to the bottom of blind holes. Overall length is 1.875 inches with a shank diameter of 0.141 inches. Machinists and toolroom technicians use this tap in CNC machining centers, drill presses, and manual tapping setups.

This tap is suited for blind hole threading operations in ferrous and non-ferrous materials. Rated material applications include alloy steel, aluminum, carbon steel, die steel, hardened steel, and stainless steel, covering a broad range of production and toolroom scenarios. The right-hand thread direction and 3B class of fit make it appropriate for standard fastener and assembly applications in aerospace, automotive, and precision manufacturing environments. Tapping depth reaches 0.559 inches, and thread length measures 0.295 inches, keeping it well-matched to shallow blind hole geometries common in small-fastener work.

Key Features

• Thread forming (cold-form) design strengthens the thread by displacing material rather than cutting chips
• Modified bottoming chamfer with 2 to 2.5 chamfered threads for threading close to hole bottoms
• Cobalt construction provides heat and wear resistance in tough alloys and hardened steels
• Bright finish suitable for use with standard tapping fluids and cutting oils
• H3 thread limit and 3B class of fit for consistent dimensional accuracy
• No coolant-through requirement simplifies setup in standard machine and manual applications

Compatibility

Designed as an OEM-style thread forming tap for 4-40 UNC blind hole applications in alloy steel, aluminum, carbon steel, die steel, hardened steel, and stainless steel workpieces.

Installation Notes

Thread forming taps require a specially sized forming tap drill, which differs from a standard tap drill — consult a forming tap drill chart for the correct hole size before use. Apply an appropriate tapping fluid or cutting oil for the workpiece material to reduce friction and extend tool life. Secure the workpiece and align the tap perpendicular to the hole to avoid tap breakage, particularly critical in small 4-40 sizes. Follow all applicable shop safety procedures and machine guarding requirements when operating powered tapping equipment.