Osg 1400105900 Thread Forming Tap 4-40 Unc Plug Cobalt

Product Description

The OSG 1400105900 is a thread forming tap in the HY-PRO NRT series, designed to cut 4-40 UNC internal threads using a chipless cold-forming process. Built from cobalt high-speed steel with a bright finish, this plug chamfer tap is suited for through-hole threading applications where thread integrity and surface finish quality are critical. The H3 thread limit and Class 3B fit make it appropriate for precision threaded assemblies. At 1.875 inches overall length with a 0.295-inch thread length and 0.559-inch tapping depth, it fits standard toolholders used in CNC and manual tapping operations.

This tap is intended for threading 4-40 UNC through-holes in a range of metallic workpiece materials. Thread forming rather than cutting displaces material rather than removing it, producing stronger threads with no chips to clear. It is commonly used in machine shops, production environments, and maintenance operations where small-diameter, fine-tolerance threaded holes are required in alloy steel, carbon steel, stainless steel, aluminum, die steel, and hardened steel components.

Key Features

• Chipless thread forming process produces stronger threads and eliminates chip evacuation concerns in through-hole applications
• Cobalt high-speed steel construction provides heat and wear resistance when tapping harder materials including hardened steel and stainless steel
• Plug chamfer with 4 to 4.5 chamfered threads allows progressive thread engagement for controlled forming pressure
• H3 thread limit and Class 3B fit deliver consistent, precision thread geometry for tight-tolerance assemblies
• Right-hand thread direction, 40 threads per inch, 4-40 UNC standard
• Bright finish with no coolant-through requirement simplifies setup in standard tapping applications

Compatibility

Designed for through-hole threading of 4-40 UNC right-hand threads in alloy steel, aluminum, carbon steel, die steel, hardened steel, and stainless steel workpieces. Material application codes P and N apply.

Installation Notes

Thread forming taps require the correct tap drill size for the material and thread form — consult a thread forming drill chart before selecting the pilot hole diameter, as forming taps use larger pilot holes than cutting taps. Apply appropriate tapping fluid or cutting oil for the workpiece material, particularly when working with stainless or hardened steel. Use a calibrated torque-limiting tapping attachment or CNC rigid tap cycle to avoid tap breakage in small-diameter applications. Ensure the workpiece is securely fixtured and the tap is properly aligned before engagement.