Osg 1227200 Spiral Point Tap 7/16-20 Unf 3 Flute Hss

Product Description

The OSG 1227200 is a spiral point plug tap designed for cutting 7/16-20 UNF right-hand threads in a wide range of ferrous and non-ferrous materials. Built from high-speed steel (HSS) with a bright finish, this tap is suited for through-hole tapping applications where chips are pushed ahead of the cutting edge rather than backed out of the hole. It features 3 flutes, an H2 thread limit for close-tolerance work, and an overall length of 3.156 inches with a thread length of 0.882 inches. Licensed machinists, maintenance technicians, and tool-room professionals use this tap in both production and repair contexts.

The 1227200 is appropriate for tapping through holes in aluminum, cast aluminum, cast iron, low-carbon steel, medium-carbon steel, high-carbon steel, and hardened steel. Its plug chamfer style makes it a general-purpose starting tap for most through-hole threading operations. The spiral point geometry drives chips forward, keeping the flutes clear and reducing the risk of chip packing in moderate-depth applications. Series 105 designation places this tap within OSG's standard spiral point product line.

Key Features

• 7/16-20 UNF thread form with H2 thread limit for close-tolerance fits
• Spiral point geometry pushes chips forward for through-hole tapping
• 3-flute design balances chip clearance and cutting edge strength
• High-speed steel construction handles a broad range of workpiece materials
• Bright finish with no coating — allows visual wear inspection
• Right-hand thread direction, no coolant-through requirement

Compatibility

Designed as a standard spiral point plug tap for through-hole tapping of 7/16-20 UNF threads. Compatible with aluminum, cast aluminum, cast iron, low-carbon steel, medium-carbon steel, high-carbon steel, and hardened steel workpieces. Fits standard 7/16-20 tap holders and tapping heads with a 0.323-inch shank diameter.

Installation Notes

This tap is intended for use by machinists or maintenance technicians operating drill presses, CNC machining centers, or manual tapping equipment. Secure the workpiece firmly and ensure the pilot hole diameter is correct for 7/16-20 UNF before tapping. Use appropriate cutting fluid for the workpiece material to extend tap life and improve thread quality. Inspect the tap for wear or chipping before each use and replace if cutting edges are damaged.