Osg 1400105105 Thread Forming Tap 4-40 Unc Bottoming Tin

Product Description

The OSG 1400105105 is a thread forming tap designed for 4-40 UNC blind hole threading applications. Unlike cutting taps, thread forming taps cold-form the thread profile without producing chips, reducing the risk of chip packing in blind holes. Built from cobalt high-speed steel and finished with a titanium nitride (TiN) coating, this tap handles demanding materials including alloy steel, stainless steel, hardened steel, carbon steel, die steel, and aluminum. The bottoming chamfer with 1 to 1.5 chamfered threads allows threading close to the bottom of a blind hole. It carries an H5 thread limit and produces a Class 2B fit, standard for general-purpose fastener applications.

This tap is suited for machine shop, maintenance, and production threading in both light and heavy manufacturing environments. Its 4-40 UNC thread size targets small fastener work common in instrumentation, electronics enclosures, and precision assemblies. The right-hand thread direction is compatible with standard tapping heads and CNC tapping cycles. The HY-PRO NRT series designation identifies it within the OSG product line as a form tap optimized for ductile and semi-ductile workpiece materials where chip-free threading is an advantage.

Key Features

• Thread forming (chipless) design eliminates chip evacuation concerns in blind holes
• Cobalt high-speed steel construction for heat and wear resistance in tough alloys
• TiN coating reduces friction and extends tool life across a wide range of workpiece materials
• Bottoming chamfer (1 to 1.5 threads) maximizes usable thread depth in blind holes
• H5 thread limit with Class 2B fit for standard general-purpose threading tolerances
• No coolant-through requirement simplifies machine setup

Compatibility

Designed for use in alloy steel, aluminum, carbon steel, die steel, hardened steel, and stainless steel workpieces. Intended for 4-40 UNC blind hole applications where chipless thread forming is required.

Installation Notes

Thread forming taps require a properly sized forming tap drill hole, which differs from a standard cut tap drill size — consult the OSG HY-PRO NRT series drill chart for the correct pre-drill diameter for 4-40 UNC. Install using a tapping head, CNC rigid tapping cycle, or manual tap wrench rated for the shank size. Ensure the workpiece is securely fixtured before tapping to prevent tap breakage in small-diameter applications. Apply appropriate tapping fluid or cutting oil for the workpiece material to reduce forming torque and extend tap life.