Osg 1650511708 Spiral Flute Tap 3/8-16 Unc Bottoming

Product Description

The OSG 1650511708 is a spiral flute tap designed for cutting 3/8-16 UNC internal threads in a wide range of metallic workpiece materials. Built from powdered metal and finished with a V coating, it delivers improved wear resistance and heat dissipation compared to standard high-speed steel taps. The bottoming chamfer allows threading close to the bottom of blind holes where entry-style taps cannot reach. With a 45-degree helix angle, the flutes efficiently evacuate chips upward, reducing the risk of chip packing during the tapping cycle. This tap carries a 2B class of fit and an H5 thread limit, making it suitable for standard tolerance threaded assemblies. Machinists and toolroom professionals install this tap in CNC machining centers, drill presses, and tapping arms.

This tap is well suited for production and job-shop applications involving alloy steel, aluminum, cast aluminum, cast iron, high-carbon steel, low-carbon steel, medium-carbon steel, stainless steel, and hardened steel. The bottoming chamfer and spiral flute geometry make it the right choice when full thread depth in blind holes is required. The right-hand thread direction matches standard right-hand fastener specifications. It is sold individually and fits into standard tap holders sized for a 0.381-inch shank diameter.

Key Features

• Bottoming chamfer allows threading to the floor of blind holes
• 45-degree right-hand helix angle promotes upward chip evacuation in blind-hole applications
• Powdered metal construction with V coating for extended tool life and heat resistance
• H5 thread limit and 2B class of fit for standard-tolerance UNC threaded holes
• Compatible with a broad range of ferrous and non-ferrous workpiece materials including stainless steel and hardened steel
• No coolant-through feature — suited for flood coolant or dry tapping setups

Compatibility

Designed for use in materials including alloy steel, aluminum, cast aluminum, cast iron, hardened steel, high-carbon steel, low-carbon steel, medium-carbon steel, and stainless steel. Fits standard tap holders and collet chucks accepting a 0.381-inch shank diameter. Intended for 3/8-16 UNC right-hand threaded applications requiring a 2B class of fit.

Installation Notes

Install in a rigid tap holder or floating tap adapter to maintain axial alignment and prevent thread lead errors. Power down or de-energize the machine before changing tooling. Apply cutting fluid appropriate to the workpiece material — sulfurized or chlorinated cutting oil is commonly used with ferrous metals. Verify tapping depth setup before running production to avoid bottoming out the tap body against the hole floor.