Osg 1405008408 Thread Forming Tap 5/16-18 Unc Bottoming

Product Description

The OSG 1405008408 is a thread forming tap in the EXOTAP VP-NRT series, designed for cold-forming internal threads without cutting or producing chips. Sized for 5/16-18 UNC threads, it features a bottoming chamfer of 1 to 1.5 threads, making it suitable for threading close to the bottom of a blind hole. Manufactured from powdered metal high-speed steel with a TiCN (titanium carbonitride) coating, it delivers high wear resistance and reduced friction in demanding tapping applications. Thread limit is H5 with a Class 3B fit, and the tool is designed for right-hand thread direction. Installed by machinists and tool-and-die professionals in production and job-shop environments.

This tap is built for blind hole threading across a wide range of workpiece materials, including alloy steel, carbon steel, die steel, hardened steel, stainless steel, and aluminum. The thread forming process displaces material rather than cutting it, producing stronger threads with improved surface finish in ductile materials. The bottoming chamfer allows threading to within one to two pitches of a hole bottom, which is critical in applications with shallow blind holes or tight depth tolerances. Typical applications include precision machined components, tooling fixtures, and structural assemblies where thread integrity is essential.

Key Features

• 5/16-18 UNC thread size with Class 3B fit and H5 thread limit for close-tolerance threading
• Bottoming chamfer (1 to 1.5 threads) enables threading near the bottom of blind holes
• Powdered metal high-speed steel construction provides toughness and wear resistance over standard HSS
• TiCN coating reduces friction and extends tool life in ferrous and non-ferrous materials
• Chipless thread forming process eliminates chip evacuation concerns in blind hole applications
• Coolant-through design not required; compatible with external cutting fluid application

Compatibility

Suitable for use in alloy steel, carbon steel, die steel, hardened steel, stainless steel, and aluminum workpieces. Designed for blind hole threading applications requiring 5/16-18 UNC Class 3B threads. Part of the OSG EXOTAP VP-NRT series (Series 14050).

Installation Notes

Thread forming taps require a specific tap drill size larger than that used for cut taps — consult OSG or standard thread forming drill charts for the correct pre-drill diameter before use. Power down and secure the workpiece in a machine tool or tapping fixture before beginning the operation. Apply appropriate tapping fluid or cutting oil for the workpiece material to reduce torque and extend tool life. This tool is intended for use by qualified machinists or tooling professionals familiar with thread forming processes and machine tapping procedures.