Osg 0140801 Spiral Flute Tap 5/16-24 Unf Bottoming

Product Description

The OSG 0140801 is a spiral flute bottoming tap designed for threading 5/16-24 UNF right-hand internal threads in difficult-to-machine materials. Built from powdered metal and finished with a steam oxide coating, this tap handles stainless steel, hardened steel, titanium, and high-nickel alloys where standard high-speed steel taps fall short. The modified bottoming chamfer allows threading close to the bottom of blind holes. With a 10-degree helix angle and three flutes, it efficiently evacuates chips in tough materials. Overall length is 2.718 inches and thread length is 0.445 inches. This is a Series 313NI tap with an H4 thread limit and a 2B class of fit.

This tap is suited for CNC machining centers, manual mills, and drill press tapping operations where UNF threads are required in hard or exotic alloys. The spiral flute geometry makes it particularly effective in blind-hole applications common in aerospace, automotive, and industrial manufacturing. It is a single-piece tool intended for use with standard tap holders or floating tap adaptors compatible with its 0.168-inch shank diameter. Licensed machinists and toolroom technicians are the primary users.

Key Features

• Modified bottoming chamfer for threading close to the bottom of blind holes
• Powdered metal construction for increased wear resistance in hard and exotic materials
• Steam oxide coating reduces friction and improves lubrication retention
• Spiral flute design promotes efficient chip evacuation in difficult-to-machine alloys
• H4 thread limit with 2B class of fit for standard UNF tolerance requirements
• Right-hand thread direction, 10-degree helix angle, no coolant-through

Compatibility

Designed for cutting 5/16-24 UNF internal threads in stainless steel, hardened steel, titanium, and high-nickel alloys. Part of the OSG Series 313NI product line.

Installation Notes

Installation and use should be performed by qualified machinists familiar with tapping operations and speeds appropriate for the workpiece material. Power down or disengage the spindle before loading or unloading the tap. Use appropriate cutting fluid or tapping compound for the material being threaded to extend tool life and reduce risk of tap breakage. Follow machine manufacturer guidelines and applicable shop safety standards when operating tapping equipment.