Osg 1400105505 Thread Forming Tap 4-40 Unc Cobalt Tin

Product Description

The OSG 1400105505 is a thread forming tap in the HY-PRO NRT series, designed for cold-forming internal threads without cutting chips. It produces a 4-40 UNC right-hand thread in blind holes, working by displacing material rather than removing it, which results in stronger thread walls and eliminates chip-clearing concerns in deep or enclosed bores. Built from cobalt high-speed steel with a titanium nitride (TiN) coating, this tap handles elevated heat and abrasion in demanding machining environments. The modified bottoming chamfer with 2 to 2.5 chamfered threads allows threading close to the bottom of a blind hole. Overall length is 1.875 inches with a shank diameter of 0.141 inches. Installed by machinists and tool-and-die tradespeople on CNC and manual equipment.

This tap is suited for blind hole threading applications in both production and job-shop settings. The 4-40 UNC thread size and H5 thread limit make it appropriate for small-fastener work in precision assemblies, instrument hardware, and electronic enclosures. Material application includes alloy steel, aluminum, carbon steel, die steel, hardened steel, and stainless steel, covering a wide range of workpiece materials. The TiN coating extends tool life when running higher spindle speeds or working harder alloys. Class of fit is 2B, the standard for most general-purpose UNC threaded holes.

Key Features

• Thread forming (chipless) design strengthens thread walls by cold-working the material
• Cobalt HSS construction resists heat buildup in difficult-to-machine alloys and stainless steel
• TiN coating reduces friction and extends tool life at higher cutting speeds
• Modified bottoming chamfer (2 to 2.5 threads) enables threading close to the bottom of blind holes
• H5 thread limit and 2B class of fit meet standard UNC tolerance requirements
• Right-hand thread direction compatible with conventional tapping setups

Compatibility

Designed for blind hole threading in workpieces made from alloy steel, aluminum, carbon steel, die steel, hardened steel, and stainless steel. Produces 4-40 UNC threads to a 2B class of fit with H5 thread limit.

Installation Notes

Thread forming taps require a specific tap drill size matched to the desired thread form fill — consult a forming tap drill chart for the correct hole diameter before use, as standard cut-tap drill sizes do not apply. Power down and secure the workpiece before setup. Use a tapping fluid or cutting oil appropriate for the workpiece material, particularly with stainless steel or hardened alloys. No coolant-through capability on this tap; flood or brush lubrication should be applied externally.