Osg 1625556127 Thread Forming Tap 5/16-18 Unc 2B

Product Description

The OSG 1625556127 is a thread forming tap designed for producing internal threads without cutting, using plastic deformation to create stronger, chip-free threads. Built from cobalt high speed steel with a V-coating finish, this tap is engineered for demanding tapping applications where thread integrity and tool life are critical. It is configured for 5/16-18 UNC threads with a 2B class of fit, a semi-bottoming chamfer, and an H7 thread limit. With an overall length of 5.9055 inches and a thread length of 0.5551 inches, it is suited for production and maintenance environments where consistent thread quality is required. Licensed machinists and tool and die professionals are the primary users.

This tap is used in both production shop and maintenance-repair-operations settings where thread forming is preferred over thread cutting. The semi-bottoming chamfer allows tapping close to the bottom of blind holes while still providing enough lead for reliable thread formation. It is well suited for applications involving aluminum, cast aluminum, carbon steel, alloy steel, die steel, stainless steel, hardened steel, high-nickel alloy, and titanium workpieces. The right-hand thread direction and standard UNC profile make it a practical choice for general fastener thread production across a wide range of industries.

Key Features

• Thread forming design produces chip-free internal threads through material displacement, reducing tap breakage risk
• Cobalt high speed steel construction provides heat and wear resistance in tough materials
• V-coating finish reduces friction and extends tool life in demanding materials
• Semi-bottoming chamfer allows tapping close to the bottom of blind holes
• H7 thread limit ensures consistent 2B class of fit for standard UNC fastener compatibility
• Right-hand thread direction for standard tapping operations

Compatibility

Designed for tapping 5/16-18 UNC internal threads in aluminum, cast aluminum, carbon steel, alloy steel, die steel, stainless steel, hardened steel, high-nickel alloy, and titanium. Part of OSG Series 16255.

Installation Notes

Thread forming taps require the correct pilot hole diameter for the material being tapped — use manufacturer-recommended forming tap drill charts rather than standard cut tap drill sizes, as forming taps require a larger pilot hole. Always ensure the workpiece is securely fixtured and use an appropriate tapping fluid for the material. Power down or disengage the spindle before changing taps. Follow applicable shop safety standards and tooling manufacturer guidelines for speed and feed rates appropriate to the material.