Osg 1762301 Spiral Flute Tap 9/16-18 Unf Modified Bottoming

Product Description

The OSG 1762301 is a spiral flute tap designed for cutting 9/16-18 UNF internal threads in a range of ferrous materials. Built from vanadium high-speed steel (HSS) with a steam oxide coating, it delivers reliable wear resistance and lubricity in production and maintenance threading applications. The 45-degree helix angle drives chips up and out of the hole, making it well-suited for blind-hole tapping where chip evacuation is critical. The modified bottoming chamfer allows threading close to the bottom of a blind hole. This tap is sized at 3-19/32 inches overall length with a thread length of 0.665 inches, and carries an H3 thread limit with a 3B class of fit for standard precision unified thread applications.

This tap is intended for use in stainless steel, high-carbon steel, low-carbon steel, and medium-carbon steel workpieces. It is a practical choice for machine shops, maintenance facilities, and field service operations requiring accurate UNF threads in blind or through holes. The spiral flute design makes it particularly effective in CNC and manual tapping machines where consistent chip management is needed. It is sold individually and fits standard tap holders sized for its 0.381-inch shank diameter.

Key Features

• 45-degree right-hand spiral flute for upward chip evacuation in blind holes
• Modified bottoming chamfer allows threading to near the bottom of a blind hole
• Vanadium high-speed steel construction for improved toughness and wear resistance
• Steam oxide coating reduces friction and improves lubricity during cutting
• H3 thread limit, 3B class of fit for standard UNF tolerance applications
• Series 303 — 9/16-18 UNF, compatible with standard tap holders for the shank size

Compatibility

Designed for threading 9/16-18 UNF blind and through holes in stainless steel, high-carbon steel, low-carbon steel, and medium-carbon steel. Fits standard tap holders accepting a 0.381-inch shank diameter.

Installation Notes

Install and operate this tap using a properly sized tap holder or collet chuck rated for the shank diameter; use of an undersized or worn holder can cause tap breakage or thread inaccuracy. Always apply a cutting fluid appropriate for the workpiece material — sulfurized oil or water-soluble coolant is commonly used with HSS taps in steel. Ensure the workpiece is securely fixtured and the tap is aligned perpendicular to the hole before engaging. Follow shop safety practices and relevant machine guarding requirements when tapping on powered equipment.