Osg 1650509508 Spiral Flute Tap 6-40 Unf Bottoming

Product Description

The OSG 1650509508 is a spiral flute bottoming tap designed for right-hand internal threading in a wide range of metallic workpiece materials. It cuts a 6-40 UNF thread profile to a 2B class of fit with an H2 thread limit, making it suitable for precision tapping applications where controlled thread tolerance is required. The tap is manufactured from powdered metal and carries a TiCN (V) coating, which provides elevated hardness and lubricity compared to uncoated HSS tooling. With a 45-degree helix angle, it is engineered to pull chips back through the flutes, making it effective in blind-hole applications. Overall length is 2.25 inches with a thread length of 0.248 inches and a tapping depth of 20.00 mm.

This tap is intended for use in blind-hole bottoming applications where thread engagement must extend close to the bottom of the bore. The 45-degree spiral flute geometry aids chip evacuation in ductile materials, including low-, medium-, and high-carbon steel, alloy steel, stainless steel, cast iron, cast aluminum, and hardened steel. It is suited for CNC machining centers, manual tapping, and production environments where consistent thread quality across multiple materials is required. The 6-40 UNF size is commonly used in precision instrument, fastener, and light mechanical assembly work.

Key Features

• 6-40 UNF thread form, 2B class of fit, H2 thread limit for controlled tolerance
• 45-degree helix angle spiral flute design for effective chip evacuation in blind holes
• TiCN (V proprietary) coating improves wear resistance and reduces built-up edge on steel and stainless
• Powdered metal construction provides toughness and fine grain structure compared to standard HSS
• Bottoming chamfer allows threading to within a few pitches of the hole bottom
• Right-hand flute and right-hand thread, no coolant-through requirement

Compatibility

Rated for use in alloy steel, aluminum, cast aluminum, cast iron, hardened steel, high-carbon steel, low-carbon steel, medium-carbon steel, and stainless steel workpiece materials. Material application codes P, M, K, N, and H per ISO designation. Part of OSG Series 16505.

Installation Notes

This tap is installed and operated by machinists and tooling technicians on CNC machining centers or manual drill presses equipped with a tapping head or torque-limiting tap holder. Ensure the spindle is stopped and the machine is in a safe state before changing tooling. Use the appropriate cutting fluid or tapping compound for the workpiece material to extend tool life and maintain thread quality. Do not reverse the tap under power without confirming the machine and holder support reversing cycles, as this can result in tap breakage in blind holes.