Osg 1102800 Straight Flute Tap 1/2-20 Unf Plug Hss

Product Description

The OSG 1102800 is a straight flute plug tap designed for cutting internal threads in a range of ferrous and non-ferrous metals. Built from high-speed steel with a bright uncoated finish, this tap produces 1/2-20 UNF right-hand threads using 4 straight flutes and a plug chamfer. The plug chamfer provides a gradual thread lead-in, making it well suited for through-hole applications where the tap can pass fully through the workpiece. With an overall length of 3-3/8 inches and a thread length of 1-21/32 inches, it fits standard tap holders and machine spindles used in CNC, manual mill, and drill press setups. Thread limit is H1, indicating a close tolerance suitable for general-purpose UNF threading.

This tap is intended for production and maintenance threading operations across a wide variety of materials. The material application list covers aluminum, cast aluminum, cast iron, high-carbon steel, low-carbon steel, and medium-carbon steel, making it a versatile choice for machine shops, maintenance facilities, and industrial production lines. It is installed by machinists and tool-and-die professionals working in metalworking environments where consistent thread quality and dimensional accuracy are required. The 1/2-20 UNF specification is common in fastener-intensive assemblies across automotive, aerospace tooling support, and general fabrication.

Key Features

• 1/2-20 UNF thread form with H1 thread limit for close-tolerance general-purpose threading
• Plug chamfer provides gradual lead-in, optimized for through-hole tapping
• 4 straight flutes for chip formation in a broad range of metals
• High-speed steel construction with bright uncoated finish
• Right-hand thread direction, compatible with standard tap holders and spindles
• No coolant-through requirement, simplifying setup on standard equipment

Compatibility

Designed as an OEM-style straight flute plug tap for standard 1/2-20 UNF threading operations. Fits tap holders sized for a 0.367-inch shank diameter. Part of OSG Series 101.

Installation Notes

This tap is installed by qualified machinists using a tapping head, CNC spindle, or hand tap wrench appropriate for the 0.367-inch shank. Always secure the workpiece and ensure the tap is properly aligned with the pilot hole before engagement to prevent tap breakage. Use a cutting fluid or tapping compound appropriate for the workpiece material; dry tapping in steel is not recommended. Inspect the tap for wear or chipping before each use, particularly in production environments where tool cycling is frequent.