Osg 1626002308 Thread Forming Sti Tap 5/16-18 Unc H4

Product Description

The OSG 1626002308 is a thread forming STI tap designed to cut 5/16-18 UNC internal threads in a wide range of materials. Unlike cutting taps, thread forming taps displace material rather than remove it, producing stronger threads with no chips to clear. This tap features a semi-bottoming chamfer for threading close to the bottom of a blind hole, a H4 thread limit for consistent Class 3B fit tolerance, and a V finish (bright, uncoated) suited for general-purpose industrial use. Overall length is 3.937 inches with a shank diameter of 0.381 inches. It is manufactured from high-speed steel. Licensed machinists, tool and die makers, and maintenance technicians typically use this tap in production and repair applications.

This tap is suited for tapping 5/16-18 UNC threads in carbon steel, alloy steel, stainless steel, aluminum, nickel, hardened steel, and titanium alloy. The semi-bottoming chamfer allows threading in shallow blind holes where a standard taper or plug chamfer cannot reach full thread depth. The H4 thread limit and Class 3B fit make this tap appropriate for precision fastener applications requiring close thread tolerances. It is part of OSG Series 16260 and ships individually.

Key Features

• Thread forming design displaces material to produce chip-free, stronger threads
• Semi-bottoming chamfer for threading close to the bottom of blind holes
• H4 thread limit for Class 3B fit tolerance control
• High-speed steel construction for durability across a broad range of workpiece materials
• V (bright) finish — uncoated, general-purpose application
• Compatible with carbon steel, alloy steel, stainless steel, aluminum, nickel, hardened steel, and titanium alloy

Compatibility

Designed for tapping 5/16-18 UNC threads in carbon steel, alloy steel, stainless steel, aluminum, nickel, hardened steel, and titanium alloy workpieces. Produces a Class 3B internal thread fit.

Installation Notes

Use in a properly aligned tap handle, tapping head, or CNC machine to avoid tap breakage. Apply appropriate cutting fluid for the workpiece material before and during tapping. Ensure the tap drill hole diameter is correct for 5/16-18 thread forming before starting. Power down and secure the workpiece before beginning any tapping operation.