Osg 1723501 Spiral Flute Tap 1/2-20 Unf Vanadium Hss

Product Description

The OSG 1723501 is a spiral flute tap designed for cutting internal threads in a 1/2-20 UNF configuration. It is built from vanadium high-speed steel and finished with a steam oxide coating that reduces friction and helps resist corrosion during service. With a 45-degree helix angle and a modified bottoming chamfer, this tap is suited for threading holes where the thread must extend close to the bottom of a blind bore. The H5 thread limit and 2B class of fit deliver consistent tolerance control for precision threaded assemblies. Machinists, toolroom technicians, and maintenance professionals install this tap in drill presses, CNC machining centers, and manual tapping operations.

This tap is intended for use on stainless steel, high-carbon steel, low-carbon steel, and medium-carbon steel workpieces. The 45-degree spiral flute angle efficiently evacuates chips upward out of the hole, making it especially effective in blind-hole applications where chip packing is a concern. The modified bottoming chamfer allows threading to within a minimal distance of the hole bottom, which is common in automotive, aerospace, and general machining work where thread engagement length is critical.

Key Features

• 1/2-20 UNF thread form with H5 thread limit and 2B class of fit for controlled tolerance
• 45-degree right-hand spiral flute geometry promotes upward chip evacuation in blind holes
• Modified bottoming chamfer enables threading close to the bottom of a blind bore
• Vanadium high-speed steel construction provides toughness and wear resistance in steel applications
• Steam oxide coating reduces friction and provides light corrosion protection during storage and use
• 3-flute design balances chip clearance with thread-form support across the cut

Compatibility

Designed for threading stainless steel, high-carbon steel, low-carbon steel, and medium-carbon steel workpieces requiring a 1/2-20 UNF internal thread to a 2B class of fit. Part of the OSG Series 303 spiral flute tap line.

Installation Notes

Installation is performed by qualified machinists or maintenance technicians using a drill press, tapping head, or CNC machine with rigid or floating tap holders. Always ensure the pilot hole is drilled to the correct tap-drill diameter for a 1/2-20 UNF thread before tapping. Apply a suitable cutting fluid for the workpiece material, and do not exceed the tap's rated capacity for the material being cut. For blind-hole applications, verify hole depth is sufficient to accommodate the tap's overall length of 3.375 inches before starting.