Osg 0136808 Spiral Flute Tap 10-32 Unf Bottoming Ticn Hss

Product Description

The OSG 0136808 is a spiral flute bottoming tap designed for threading 10-32 UNF holes in ferrous metals. Built from vanadium high-speed steel with a TiCN (Titanium Carbonitride) coating, it delivers increased surface hardness and wear resistance compared to uncoated HSS taps. The 45-degree helix angle drives chips up and out of the flute during tapping, making it well-suited for blind-hole applications where chip evacuation is critical. At 2-3/8 inches overall length with a 3B class of fit and H2 thread limit, this tap cuts to dimensional tolerances appropriate for standard commercial fastener fits in precision assemblies.

This tap is used in machine shop, maintenance, and production environments where 10-32 UNF threads must be tapped to the bottom of a blind hole. The bottoming chamfer leaves only 1-2 thread leads of taper, allowing full threads closer to the bottom of the bore than a plug or taper tap allows. Suitable for use in stainless steel, high-carbon steel, low-carbon steel, and medium-carbon steel workpieces. The right-hand flute direction and right-hand thread cut pairs with standard CNC or manual tapping heads turning clockwise.

Key Features

• Bottoming chamfer for threading close to the bottom of blind holes
• 45-degree spiral flute helix angle promotes upward chip evacuation
• TiCN coating increases surface hardness and extends tool life in ferrous materials
• Vanadium high-speed steel substrate resists heat and abrasion
• H2 thread limit and 3B class of fit for standard commercial tolerance threads
• Three flutes provide a balance of chip room and cutting edge strength for 10-32 UNF

Compatibility

Designed for tapping 10-32 UNF threads in stainless steel, high-carbon steel, low-carbon steel, and medium-carbon steel. Part of the OSG Series 303 spiral flute tap line.

Installation Notes

This tap is installed by machinists or maintenance technicians using a tapping machine, CNC machining center, or manual tap wrench. Before tapping, confirm the pilot hole diameter is correct for a 10-32 UNF thread to achieve the desired thread engagement percentage. Apply an appropriate cutting fluid or tapping compound for the workpiece material, particularly when working in stainless steel. Never reverse the tap abruptly under load — back the tap out steadily to break and clear chips.