Osg 1400151700 Thread Forming Tap 5/8-18 Unf Cobalt

Product Description

The OSG 1400151700 is a thread forming tap designed for 5/8-18 UNF right-hand threads in blind hole applications. Unlike cutting taps, this modified bottoming tap forms threads by displacing material rather than cutting it, producing stronger threads with no chips to clear. Built from cobalt high-speed steel with a bright finish, the tap handles demanding materials including alloy steel, carbon steel, stainless steel, hardened steel, die steel, and aluminum. It carries an H4 thread limit and belongs to OSG's HY-PRO NRT Series 14001, sized at 3.813 inches overall length. Machinists and toolroom technicians select this tap when thread quality and hole-bottom reach are both critical.

This tap is suited for blind hole threading operations in production machining, maintenance, and repair environments. The modified bottoming chamfer — 2 to 2.5 chamfered threads — allows threading close to the bottom of a blind hole while still providing enough lead-in for accurate thread formation. The material application range covers a broad spectrum of ferrous and non-ferrous workpiece materials, making it a practical choice across job shop, aerospace, automotive, and general industrial applications where 5/8-18 UNF internal threads are required.

Key Features

• Thread forming design displaces material rather than cutting, producing chip-free stronger threads
• Cobalt high-speed steel construction for improved heat and wear resistance in tough alloys
• Modified bottoming chamfer (2-2.5P) enables threading close to the bottom of blind holes
• H4 thread limit for controlled fit in UNF tolerance applications
• Bright coating provides a smooth, low-friction surface for thread forming operations
• No coolant-through requirement simplifies setup on standard tapping equipment

Compatibility

Designed for use in blind hole threading of 5/8-18 UNF tapped holes in alloy steel, carbon steel, stainless steel, hardened steel, die steel, and aluminum workpieces where a right-hand thread forming tap with modified bottoming chamfer is specified.

Installation Notes

Thread forming taps require a properly sized forming tap drill hole — consult OSG or standard tap drill charts for the correct forming drill diameter for 5/8-18 UNF, as it differs from cutting tap drill sizes. Use appropriate tapping fluid or cutting oil matched to the workpiece material before starting. Secure the workpiece and ensure the tap is driven perpendicular to the hole to prevent tap breakage or thread distortion. A tap wrench, tapping head, or CNC rigid tapping cycle with synchronized feed-per-revolution equal to the thread pitch is required.