Osg 1400105800 Thread Forming Tap 4-40 Unc Plug Cobalt

Product Description

The OSG 1400105800 is a thread forming tap from the HY-PRO NRT series, designed for cold-forming internal threads in ductile metals without cutting or producing chips. Built from cobalt high-speed steel with a bright finish, this tap carries a 4-40 UNC thread form and a plug chamfer with 4 to 4.5 chamfered threads for gradual thread engagement. The H2 thread limit provides a controlled tolerance fit suitable for standard fastener applications. Overall length is 1.875 inches with a shank diameter of 0.141 inches. Installed by machinists and tool-and-die professionals in production and maintenance environments.

This tap is suited for through-hole threading operations in a range of ferrous and non-ferrous materials including alloy steel, carbon steel, die steel, hardened steel, stainless steel, and aluminum. The thread forming method displaces material rather than cutting it, resulting in stronger thread forms and no chip evacuation concerns. Typical applications include small fastener holes in precision assemblies, fixture components, and machined parts where thread integrity and tool life are priorities. Right-hand thread direction applies.

Key Features

• Cobalt high-speed steel construction for improved heat and wear resistance in tough materials
• Thread forming design produces no chips, eliminating chip-clogging in blind and through holes
• Plug chamfer with 4 to 4.5 chamfered threads for controlled entry and gradual thread engagement
• H2 thread limit for consistent tolerance control in standard 4-40 UNC threaded holes
• Bright finish with no coolant-through requirement, suitable for standard tapping fluid application
• Right-hand, through-hole threading application with a tapping depth of 0.559 inches

Compatibility

Designed for through-hole threading in alloy steel, aluminum, carbon steel, die steel, hardened steel, and stainless steel workpieces requiring a 4-40 UNC internal thread form.

Installation Notes

Thread forming taps require a properly sized forming tap drill hole, which is typically larger than a standard cut tap drill size for the same thread - consult an NRT drill chart for the correct hole diameter before use. Apply an appropriate tapping fluid or cutting oil for the workpiece material to reduce torque and extend tool life. Secure the workpiece fully before tapping and use a calibrated tap holder or CNC rigid tapping cycle to maintain alignment. Never use a thread forming tap in brittle materials such as cast iron or hardened workpieces beyond the rated material application range.