Osg 1757001 Spiral Point Tap 4-40 Unc Plug 2 Flute

Product Description

The OSG 1757001 is a spiral point tap designed for cutting 4-40 UNC internal threads in a wide range of demanding materials. Built from powdered metal and finished with a steam oxide coating, this plug-chamfer tap drives chips forward ahead of the cut, reducing clogging in through-hole applications. It carries an H2 thread limit and is rated for Class 2B and 3B fits, making it suitable for standard production threading where close tolerance control is required. With an overall length of 1.874 inches and a shank diameter of 0.141 inches, it fits standard tap holders used in machine and hand tapping setups. Licensed machinists, toolroom technicians, and maintenance mechanics are the primary users.

The OSG 1757001 is suited for through-hole threading operations in ferrous and exotic materials, including hardened steel, stainless steel, high-nickel alloy, titanium, alloy steel, and die steel. The plug chamfer makes it appropriate for through-holes where a partial-thread lead-in is acceptable. It is well matched to production environments where spiral point geometry and steam oxide lubricity help extend tool life in tough-to-machine alloys.

Key Features

• Spiral point geometry pushes chips ahead of the tap, keeping the flutes clear in through-hole applications
• Powdered metal construction provides consistent hardness and wear resistance across the full tool body
• Steam oxide coating reduces friction and helps retain cutting fluid at the tool-work interface
• H2 thread limit supports Class 2B and 3B fit requirements common in production threading
• Right-hand thread direction, 2-flute design suited for 4-40 UNC thread form
• No coolant-through feature — designed for external flood or manual lubrication

Compatibility

Rated for use in hardened steel, stainless steel, high-nickel alloy, titanium, alloy steel, and die steel. Produces 4-40 UNC threads to Class 2B and 3B fit standards per OSG Series 312.

Installation Notes

Install in a properly sized tap holder or tapping chuck; do not use a worn or loose holder as it can cause tap breakage at this small diameter. Ensure the workpiece and spindle are properly aligned before engaging the tap. Apply cutting fluid rated for the workpiece material, particularly when threading stainless steel or high-nickel alloys. Remove the tap carefully when reversing — 4-40 taps are small in cross-section and susceptible to breakage under side load.