Osg 1763905 Spiral Flute Tap 4-40 Unc Tin Vanadium Hss

Product Description

The OSG 1763905 is a spiral flute tap designed for cutting 4-40 UNC internal threads in demanding materials. Built from vanadium high-speed steel and coated with titanium nitride (TiN), it delivers extended tool life in applications where standard HSS taps wear prematurely. The 45-degree helix angle and 2-flute spiral geometry evacuate chips upward out of the hole, making this tap well-suited for blind-hole threading where chip packing is a concern. It is ground to a 2B class of fit with an H2 thread limit, meeting standard tolerance requirements for most mechanical fastening applications. Licensed machinists, toolroom operators, and precision fabricators are the typical users.

This tap is rated for use in stainless steel, high-carbon steel, low-carbon steel, and medium-carbon steel. The modified bottoming chamfer allows threading close to the bottom of a blind hole, which is useful in tight-clearance assemblies and close-tolerance fixturing. With an overall length of 2.719 inches and a thread length of 0.197 inches, the 1763905 fits standard tap holders and machines without requiring extended-reach tooling. It is a practical choice in production environments running small-diameter fastener holes in ferrous workpieces.

Key Features

• 45-degree right-hand spiral flute geometry for upward chip evacuation in blind holes
• TiN coating increases surface hardness and reduces friction for longer tool life in ferrous materials
• Modified bottoming chamfer allows threading to near-bottom depth in blind holes
• Vanadium high-speed steel base material resists heat and wear in stainless and high-carbon steels
• H2 thread limit and 2B class of fit meet standard tolerance requirements for general mechanical assemblies
• Right-hand thread direction compatible with conventional tapping setups and CNC rigid tapping cycles

Compatibility

Rated for threading stainless steel, high-carbon steel, low-carbon steel, and medium-carbon steel. Part of OSG Series 303.

Installation Notes

Installation is performed by machinists or toolroom technicians using a standard tap wrench, tapping head, or CNC machine with rigid tapping capability. Always use a cutting fluid appropriate for the workpiece material, particularly when tapping stainless steel, to prevent galling and tap breakage. Ensure the tap is properly aligned to the drilled hole before applying cutting pressure to avoid tap deflection or thread misalignment. Remove chips frequently when hand-tapping blind holes to prevent packing and tool breakage.