Osg 1232201 Spiral Point Tap 7/16-20 Unf Plug Hss

Product Description

The OSG 1232201 is a spiral point plug tap designed for cutting right-hand internal threads to a 7/16-20 UNF specification. Built from high-speed steel (HSS) with a steam oxide coating, it provides corrosion resistance and reduces friction during the threading operation. The plug chamfer distributes cutting load across several leading threads, making it well suited for through-hole tapping applications. With 3 flutes and an H3 thread limit, the 1232201 delivers consistent thread tolerance in a wide range of workpiece materials. Overall length is 3.156 inches with a thread length of 0.882 inches and a shank diameter of 0.323 inches.

This tap is rated for use in aluminum, cast aluminum, cast iron, low-carbon steel, medium-carbon steel, high-carbon steel, and hardened steel. It fits standard hand-tap holders and machine-tap holders used in CNC machining centers, drill presses, and manual tapping fixtures. The 7/16-20 UNF thread is common in automotive, hydraulic, and general mechanical assemblies where a fine-thread engagement is required for vibration resistance or precise clamping force. The Series 105 designation places it within OSG's standard HSS tap lineup.

Key Features

• 7/16-20 UNF right-hand thread for fine-thread through-hole applications
• High-speed steel construction for general-purpose tapping across ferrous and non-ferrous materials
• Steam oxide coating reduces friction and provides basic corrosion resistance
• Plug chamfer distributes cutting forces across the lead threads for smoother entry
• H3 thread limit for controlled tolerance fit in standard UNF threaded assemblies
• 3-flute design promotes chip ejection ahead of the tap in through-hole configurations

Compatibility

Designed for use in any standard tap holder accepting a 0.323-inch shank diameter. Rated for tapping aluminum, cast aluminum, cast iron, low-carbon steel, medium-carbon steel, high-carbon steel, and hardened steel workpieces.

Installation Notes

Secure the workpiece fully before tapping and ensure the tap is aligned perpendicular to the drilled hole to prevent thread damage or tap breakage. Use the appropriate cutting fluid for the workpiece material - sulfurized oil for ferrous metals and a light oil or emulsion for aluminum. Machine operators should set spindle speed and feed rate per the tap manufacturer guidelines for the specific material being threaded. Inspect the tap for wear or chipping before each use; a damaged cutting edge should be replaced before continuing.