Osg 1122700 Straight Flute Tap 1/2-20 Unf Hss Taper

Product Description

The OSG 1122700 is a straight flute tap designed to cut 1/2-20 UNF right-hand internal threads in a wide range of metals and alloys. Built from high-speed steel with a bright, uncoated finish, this tap features a taper chamfer that guides entry gradually into the workpiece for controlled thread formation. The 4-flute design provides rigidity and chip-clearing capacity suited to through-hole and open-ended applications. Overall length is 3-3/8 inches with a thread length of 1-21/32 inches, a shank diameter of 0.367 inches, and a square drive length of 0.4375 inches. The H3 thread limit establishes controlled oversize tolerance appropriate for plated or coated finished threads. This tap is installed by machinists and maintenance technicians in production and repair environments.

The 1122700 is suited for tapping aluminum, cast aluminum, cast iron, low-carbon steel, medium-carbon steel, and high-carbon steel. The taper chamfer style makes it a practical choice for starting threads in through-holes where the full chamfer length can engage before reaching full thread depth. It fits standard tap wrenches, T-handle tap wrenches, and machine collets that accept the 0.275-inch square drive. Class of fit 3B produces threads with tighter tolerance suitable for precision fastener applications in manufacturing, toolroom, and general mechanical assembly work.

Key Features

• 1/2-20 UNF right-hand thread, 3B class of fit for precision tolerance fastening
• Taper chamfer allows gradual thread engagement - well suited to through-hole applications
• H3 thread limit for controlled oversize, compatible with plated or coated threads
• High-speed steel construction provides durability across ferrous and non-ferrous materials
• 4 straight flutes support chip clearance and tap rigidity during cut
• Bright, uncoated finish - suitable for use with cutting oils and water-soluble coolants

Compatibility

Designed for use in aluminum, cast aluminum, cast iron, low-carbon steel, medium-carbon steel, and high-carbon steel workpieces. Compatible with standard tap wrenches and machine tool holders accepting a 0.275-inch square drive. Fits Series 101 OSG tap tooling categories.

Installation Notes

This tap should be installed by qualified machinists or maintenance technicians familiar with thread-cutting operations. Always ensure the workpiece is securely fixtured and the pilot hole is drilled to the correct tap drill diameter for 1/2-20 UNF before beginning. Apply an appropriate cutting fluid for the workpiece material to extend tool life and maintain thread quality. Back the tap out periodically to break chips and prevent binding, especially in deeper holes.