Osg 1170700 Straight Flute Tap 5/16-18 Unc Plug Hss

Product Description

The OSG 1170700 is a straight flute plug tap designed to cut 5/16-18 UNC internal threads in a wide range of ferrous and non-ferrous materials. Built from high-speed steel (HSS) with a bright/uncoated finish, it delivers consistent thread quality in general-purpose tapping applications. The plug chamfer - typically 3 to 5 threads - allows the tap to start easily in through-holes and blind holes with adequate clearance. With an H3 thread limit and a 3B class of fit, it produces threads within standard tolerance for most industrial and mechanical assembly applications. Three flutes provide chip clearance and help maintain cutting performance through the full thread length.

This tap is suited for hand tapping and machine tapping operations in job shop, maintenance, and production environments. It performs in aluminum, cast aluminum, cast iron, low-carbon steel, medium-carbon steel, and high-carbon steel. The right-hand thread orientation makes it compatible with standard tapping heads and CNC tapping cycles. It is a practical choice for machinists, maintenance mechanics, and tooling professionals working with 5/16-18 UNC fastener applications.

Key Features

• 5/16-18 UNC thread form with H3 thread limit for 3B class of fit tolerance
• Plug chamfer for easy entry in through-holes and adequately deep blind holes
• High-speed steel construction for durability across a broad range of workpiece materials
• Bright/uncoated finish - no coating buildup to affect thread tolerance
• 3 flutes provide chip clearance and smooth cutting action
• Right-hand thread direction compatible with standard tapping equipment

Compatibility

Designed for use in materials including aluminum, cast aluminum, cast iron, low-carbon steel, medium-carbon steel, and high-carbon steel. Fits standard tap holders and tapping heads accepting the 5/16-18 UNC plug tap shank geometry.

Installation Notes

Tapping operations should be performed by qualified machinists or maintenance professionals following applicable shop safety procedures. Ensure the workpiece is securely clamped and the correct drill size for 5/16-18 UNC threads is used before tapping. Apply appropriate cutting fluid for the workpiece material to extend tool life and improve thread finish. Reverse the tap periodically when hand tapping to break chips and prevent tap breakage.