Osg 1759301 Spiral Point Tap 4-40 Unc Plug 2 Flute

Product Description

The OSG 1759301 is a spiral point plug tap designed for threading 4-40 UNC internal threads in demanding materials. Built from powdered metal and finished with a steam oxide coating, this tap handles hardened steel, stainless steel, high-nickel alloy, titanium, alloy steel, and die steel. The two-flute spiral point geometry pushes chips forward ahead of the tap, making it well suited for through-hole threading applications. The H5 thread limit designation ensures controlled oversize tolerances for consistent thread fit. At 1.874 inches overall length with a 0.141-inch shank diameter, it fits standard tap holders and CNC tooling used in machine shop and production environments. Licensed machinists and tool-and-die professionals are the primary users of this tap.

This tap is used in through-hole tapping operations where chip evacuation is critical. Its material application range covers hardened steel, stainless steel, high-nickel alloy, titanium, alloy steel, and die steel, making it a practical choice for aerospace, medical, and industrial manufacturing setups. The right-hand thread direction and plug chamfer make it suitable for machine tapping in moderate-depth through holes. Coolant-through capability is not included, so external flood or mist coolant should be applied when working in difficult materials to maintain tool life.

Key Features

• 4-40 UNC thread size with right-hand direction for standard inch-series through-hole tapping
• Spiral point geometry pushes chips forward, reducing jamming and breakage in through holes
• Powdered metal construction provides increased wear resistance over standard HSS
• Steam oxide coating reduces friction and improves lubricity during cutting
• H5 thread limit for controlled tolerance and consistent thread fit
• Compatible with hardened steel, stainless steel, high-nickel alloy, titanium, alloy steel, and die steel

Compatibility

Designed for through-hole tapping of 4-40 UNC threads in hardened steel, stainless steel, high-nickel alloy, titanium, alloy steel, and die steel using standard tap holders accepting a 0.141-inch shank diameter.

Installation Notes

This tap should be installed by a qualified machinist in a rigid tap holder or CNC tapping attachment. Ensure the workpiece is securely fixtured and the spindle is properly aligned before beginning the tapping cycle. Apply appropriate cutting fluid or flood coolant externally to extend tool life, particularly in stainless steel and high-nickel alloys. Inspect the tap for wear or chipping regularly and replace before thread quality degrades.