Osg 1733301 Spiral Flute Tap 7/16-20 Unf 3 Flute

Product Description

The OSG 1733301 is a spiral flute tap designed for cutting right-hand internal threads in a 7/16-20 UNF thread form. Built from vanadium high-speed steel with a steam oxide finish, this tap delivers consistent performance in threading operations where chip evacuation is critical. The 45-degree helix angle drives chips up and out of the hole, making spiral flute geometry the preferred choice for blind-hole applications. The modified bottoming chamfer allows threads to be cut closer to the bottom of a blind bore than a standard taper or plug chamfer. Machinists and toolroom technicians install this tap in CNC machining centers, drill presses, and manual tapping fixtures.

This tap is suited for threading operations in stainless steel, high-carbon steel, low-carbon steel, and medium-carbon steel workpieces. The H3 thread limit designates a controlled oversize tolerance that accommodates standard Class 2B and 3B fit requirements in UNF threaded holes. With an overall length of 3.156 inches and a 3-flute configuration, it fits standard tap holders designed for 7/16-inch shank tooling. It is appropriate for both production and maintenance shop environments where 7/16-20 UNF tapped holes are required.

Key Features

• 45-degree right-hand spiral flute geometry evacuates chips upward, ideal for blind-hole threading
• Modified bottoming chamfer allows threading close to the bottom of blind bores
• Vanadium high-speed steel construction provides wear resistance in ferrous materials
• Steam oxide coating reduces friction and provides light corrosion resistance during storage and use
• H3 thread limit supports Class 2B and 3B fit tolerance requirements
• Right-hand flute direction with right-hand thread for standard UNF tapping operations

Compatibility

Rated for use in stainless steel, high-carbon steel, low-carbon steel, and medium-carbon steel. Designed for 7/16-20 UNF blind-hole threading applications using standard tap holders that accept the listed shank and square dimensions.

Installation Notes

This tap is installed by machinists and toolroom technicians using standard tap holders or floating tap adapters. Always ensure the workpiece is securely fixtured and that the spindle or tapping arm is properly aligned with the drilled pilot hole before engagement. Apply appropriate cutting fluid for the workpiece material to extend tool life and maintain thread quality. Inspect the tap for wear or chipping between operations, and never force a worn or damaged tap through a hole.