Osg 1709301 Spiral Flute Tap 8-32 Unc 3 Flute 2B

Product Description

The OSG 1709301 is a spiral flute tap designed for threading 8-32 UNC internal threads in difficult-to-machine materials. Built from powdered metal and finished with a steam oxide coating, this tap handles stainless steel, hardened steel, titanium, and high-nickel alloys where standard HSS taps fall short. The modified bottoming chamfer allows threading closer to the bottom of blind holes. With a 10-degree helix angle and right-hand spiral flute direction, chips are pulled back out of the hole during the tapping operation, reducing packing and breakage risk in tough materials. Overall length is 2.125 inches with a shank diameter of 0.323 inches.

This tap is suited for precision machining environments where 2B class of fit tolerances are required. The H3 thread limit provides consistent oversize control for plated or close-tolerance assemblies. It is commonly used in aerospace, defense, medical, and industrial fabrication applications where the base materials resist cutting. The Series 313NI designation identifies this as an OSG line engineered specifically for nickel-based and other hard alloys. Machinists, tool-and-die makers, and CNC operators working in job shops or production facilities are the primary users.

Key Features

• 8-32 UNC thread form with H3 thread limit for controlled 2B class of fit
• Powdered metal construction provides wear resistance in hard and abrasive materials
• Steam oxide coating reduces friction and improves chip flow in tough alloys
• Modified bottoming chamfer for threading close to the bottom of blind holes
• 10-degree right-hand helix angle evacuates chips upward, reducing tap breakage
• Rated for stainless steel, hardened steel, titanium, and high-nickel alloys

Compatibility

Designed for cutting 8-32 UNC internal threads in stainless steel, hardened steel, titanium, and high-nickel alloys. No coolant-through capability; suitable for use with cutting fluid applied externally.

Installation Notes

This tap is installed by qualified machinists using a tapping head, CNC machine, or manual tap wrench sized for the 0.323-inch shank. Always use an appropriate cutting fluid for the work material — sulfurized or chlorinated oils are common choices for stainless and high-nickel alloys. Ensure the pilot hole diameter matches the recommended tap drill size for 8-32 UNC before starting. Inspect for wear or chipping between uses, as powdered metal tooling in hard materials should not be run past its service life.