Osg 1432505 Spiral Flute Tap 1/2-20 Unf Bottoming Tin Hss

Product Description

The OSG 1432505 is a spiral flute tap designed for cutting right-hand internal threads to the 1/2-20 UNF standard. It features a bottoming chamfer for threading close to the bottom of blind holes, making it a go-to tool for precision thread work in production and maintenance environments. Built from high-speed steel with a TiN (titanium nitride) coating, it delivers extended tool life compared to uncoated HSS taps. The 50-degree helix angle promotes efficient chip evacuation up and out of the hole, reducing the risk of chip packing in blind-hole applications. Machinists, tool-and-die technicians, and maintenance trades use this tap with standard tap handles, CNC tapping heads, or drill press setups.

This tap is suited for threading aluminum, cast aluminum, cast iron, low-carbon steel, medium-carbon steel, and high-carbon steel. It is a strong candidate for general metalworking, fixture fabrication, automotive component repair, and industrial maintenance applications where a fine-thread 1/2-20 UNF bottoming tap is required. The 3B class of fit and H3 thread limit ensure compatibility with standard commercial tolerance threaded fasteners and fittings. The spiral flute design is particularly effective in blind holes where chip clearance is critical.

Key Features

• Bottoming chamfer allows threading to within 1-2 thread pitches of the bottom of a blind hole
• 50-degree right-hand spiral flute evacuates chips efficiently in blind-hole applications
• TiN coating increases surface hardness and reduces friction for longer tool life
• H3 thread limit and 3B class of fit meet standard commercial tolerance requirements
• High-speed steel construction handles a wide range of ferrous and non-ferrous workpiece materials
• No coolant-through design suits conventional hand-tapping and standard machine tapping operations

Compatibility

Designed for cutting 1/2-20 UNF right-hand internal threads in aluminum, cast aluminum, cast iron, low-carbon steel, medium-carbon steel, and high-carbon steel workpieces. Compatible with standard 1/2-20 UNF threaded fasteners and fittings requiring a 3B class of fit.

Installation Notes

Always secure the workpiece before tapping and ensure the starting hole is drilled to the correct tap drill size for 1/2-20 UNF thread engagement. Apply cutting fluid appropriate for the workpiece material to reduce heat and extend tap life. When using this tap in a machine setup, verify that the tapping head or CNC spindle is configured for the correct feed rate to match the 20 threads-per-inch pitch. Inspect the tap for wear or chipping before each use, and replace if thread form or flute condition is compromised.