Osg 1005201608 Straight Flute Tap 1/2-20 Unf Bottoming Ticn

Product Description

The OSG 1005201608 is a straight flute bottoming tap designed for threading 1/2-20 UNF internal threads in production and maintenance machining applications. It is manufactured from powdered metal and coated with TiCN (Titanium Carbonitride), which improves wear resistance and allows higher cutting speeds compared to standard high-speed steel taps. The tap features 4 flutes, a 3B class of fit, H3 thread limit, and right-hand thread direction. Overall length is 3-3/8 inches with a thread length of 1-21/32 inches and a shank diameter of 0.367 inches. Machinists and toolroom professionals use this tap for finish threading close to the bottom of blind holes.

This bottoming tap is suited for aluminum and cast iron workpieces where a full thread depth to the bottom of a blind hole is required. The bottoming chamfer geometry leaves only 1 to 2 threads of lead-in, making it the final-pass tap in a standard tapping sequence following a taper and plug tap. It is appropriate for manual tapping setups, CNC machining centers, and drill press tapping operations. The TiCN coating extends tool life in abrasive materials and reduces built-up edge in aluminum. It is part of OSG Series 10052.

Key Features

• Bottoming chamfer for threading to the bottom of blind holes
• TiCN coating for improved wear resistance and longer tool life
• Powdered metal construction for increased toughness over conventional HSS
• 4-flute design suitable for aluminum and cast iron applications
• H3 thread limit and 3B class of fit for standard tolerance internal threads
• Right-hand thread direction, no coolant-through requirement

Compatibility

Designed for cutting 1/2-20 UNF right-hand internal threads in aluminum and cast iron. Compatible with standard 1/2-20 tapping chucks and tap holders sized for a 0.367-inch shank diameter.

Installation Notes

This tap is installed by a machinist or toolroom technician using a tapping chuck, tap wrench, or CNC rigid tapping cycle. 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 tapping. Use appropriate cutting fluid for the workpiece material — sulfurized oil for cast iron and a water-soluble or petroleum-based fluid for aluminum. When used as a bottoming tap, complete the thread with a taper and plug tap first to avoid overloading the tool.