Osg 1430001 Spiral Flute Tap 1/4-20 Unc Hss Oxide

Product Description

The OSG 1430001 is a spiral flute tap designed for cutting internal threads in a wide range of metallic workpieces. It cuts a 1/4-20 UNC right-hand thread and meets a 3B class of fit, making it appropriate for standard tolerance threaded holes in production and maintenance applications. The tap is manufactured from high-speed steel and finished with a steam oxide coating that provides mild lubricity and corrosion resistance during use. With a 50-degree helix angle and three flutes, it pulls chips up and out of the hole efficiently, which is particularly valuable when tapping blind holes. Overall length is 2.5 inches. This tap is installed by machinists, tool and die technicians, and maintenance mechanics working in metalworking, fabrication, and industrial repair settings.

The OSG 1430001 is suited for tapping aluminum, cast aluminum, cast iron, low-carbon steel, medium-carbon steel, and high-carbon steel. It is a plug-chamfer design, meaning it requires a pre-existing through-hole or drilled blind hole and is not intended for starting threads from a solid surface without a lead hole. Typical applications include creating threaded fastener holes in machined components, repair of stripped threads, and production threading operations where a 1/4-20 UNC thread form is required. The H3 thread limit ensures consistent fit with standard 3B tolerance hardware.

Key Features

• 1/4-20 UNC thread form with right-hand thread direction and 3B class of fit
• 50-degree helix angle with spiral flute geometry for efficient chip evacuation in blind holes
• High-speed steel construction for durability across a broad range of workpiece materials
• Steam oxide coating provides mild lubrication and light corrosion resistance
• Plug chamfer entry suitable for through-holes and blind holes with adequate clearance depth
• H3 thread limit for consistent dimensional accuracy in standard tolerance applications

Compatibility

Designed for use in aluminum, cast aluminum, cast iron, low-carbon steel, medium-carbon steel, and high-carbon steel workpieces requiring a 1/4-20 UNC internal thread to a 3B class of fit.

Installation Notes

This tap is installed by machinists or maintenance mechanics using a tap wrench, tapping head, or machine spindle; power down all equipment and secure the workpiece before beginning. Drill the correct tap drill size for a 1/4-20 UNC thread prior to tapping, and apply appropriate cutting fluid for the workpiece material to extend tool life. Do not force the tap if resistance increases sharply, as high-speed steel taps can fracture under excessive torque. Follow applicable shop safety standards and manufacturer feed rate recommendations for the machine being used.