Osg 1600807 Straight Flute Tap 5/16-18 Unc Bottoming Hss

Product Description

The OSG 1600807 is a straight flute bottoming tap designed for cutting 5/16-18 UNC internal threads in production and repair applications. Built from high-speed steel with a nitride/oxide coating, this tap delivers consistent thread quality with reduced friction and improved wear resistance. The bottoming chamfer geometry allows threading to the base of blind holes, making it suitable for tight-tolerance fastener applications. With a 3B class of fit and H3 thread limit, it produces threads within the standard tolerance band required for most commercial and precision assemblies. Licensed machinists, tool-and-die makers, and maintenance technicians are the primary users.

This tap is suited for use in aluminum and cast iron workpieces across manual tapping, turret lathe, and CNC drilling operations. The straight flute design works best in through-hole applications and short blind holes where chip clearance is managed by the operator. The 101C series designation indicates a standard geometry configuration. The right-hand thread direction is standard for the vast majority of fastener applications. The H3 oversize limit supports plated or coated fastener clearance where a slightly looser fit is acceptable.

Key Features

• Bottoming chamfer for threading to the bottom of blind holes
• High-speed steel construction for durability across ferrous and non-ferrous materials
• Nitride/oxide coating reduces friction and improves tool life
• 3B class of fit with H3 thread limit for standard commercial tolerance
• 4 straight flutes for chip management in short blind and through-hole applications
• Compatible with aluminum and cast iron workpiece materials

Compatibility

Designed for threading 5/16-18 UNC holes in aluminum and cast iron. Suitable for use in standard tapping chucks, tap handles, and CNC rigid tapping setups that accept a 0.318-inch shank diameter.

Installation Notes

This tap should be installed in a properly aligned tapping chuck or tap wrench to prevent thread misalignment or tap breakage. Secure the workpiece fully before tapping and apply cutting fluid appropriate to the workpiece material. Reverse the tap periodically during manual operation to break and clear chips. Do not force the tap beyond its rated thread depth, particularly in blind holes where bottoming contact can cause breakage.