Osg 1601207 Straight Flute Tap 5/16-24 Unf Bottoming Hss

Product Description

The OSG 1601207 is a straight flute bottoming tap designed for cutting 5/16-24 UNF right-hand internal threads to the bottom of blind holes. Made from high-speed steel with a nitride and oxide coating, this tap delivers controlled thread engagement in both aluminum and cast iron. It carries a 3B class of fit and H3 thread limit, making it suitable for applications that require a standard tolerance fit. The 4-flute straight flute design provides chip control in short-chipping materials. Overall length is 2-23/32 inches with a thread length of 1-1/8 inches.

This tap is intended for use in machining, fabrication, and maintenance environments where 5/16-24 UNF threads are required. The bottoming chamfer allows threading close to the bottom of blind holes, a critical requirement in precision assembly work. It is suited for use in manual tapping, CNC tapping, and drill press applications when working with aluminum and cast iron workpieces. Machinists, tool and die makers, and maintenance technicians are the primary users.

Key Features

• Bottoming chamfer for threading to the bottom of blind holes
• 4 straight flutes designed for short-chipping materials such as aluminum and cast iron
• High-speed steel construction for durability across general machining applications
• Nitride and oxide coating improves wear resistance and reduces galling
• H3 thread limit and 3B class of fit for standard tolerance internal threads
• Right-hand thread direction, 5/16-24 UNF, Series 101C

Compatibility

Designed for cutting 5/16-24 UNF internal threads in aluminum and cast iron workpieces. Compatible with standard tapping chucks, tap handles, and CNC rigid tapping setups that accept the 0.318-inch shank diameter of this tap.

Installation Notes

Secure the workpiece firmly before tapping and ensure the tap is properly aligned to avoid cross-threading or tap breakage. Use an appropriate cutting fluid for the material being tapped - sulfurized oil for cast iron and a light cutting fluid for aluminum is a common practice. For CNC applications, verify spindle speed and feed rate are appropriate for the tap size and material before running the cycle. Inspect the tap for wear or chipping regularly, as a damaged tap can compromise thread quality and may become difficult to extract from a blind hole.