Osg 1405009108 Thread Forming Tap 5/16-18 Unc Modified Bottoming

Product Description

The OSG 1405009108 is a thread forming tap in the EXOTAP VP-NRT series, designed for cold-forming internal threads without cutting. Sized for 5/16-18 UNC threads, this tap displaces material rather than removing chips, producing stronger, work-hardened threads in ductile materials. It features a modified bottoming chamfer with 2 to 2.5 chamfered threads, allowing threading close to the bottom of blind holes. The tap is manufactured from powdered metal high-speed steel and carries a TiCN coating for improved wear resistance and lubricity. Overall length is 2.719 inches with a shank diameter of 0.318 inches. This tool is installed by machinists and tool-room technicians in production and maintenance applications.

This tap is intended for blind hole threading in a range of metallic materials including alloy steel, aluminum, carbon steel, die steel, hardened steel, and stainless steel. The modified bottoming chamfer makes it well suited for applications where thread depth must be maximized in a blind hole. The EXOTAP VP-NRT series is engineered for demanding applications where chip evacuation is a concern, since thread forming produces no chips. It carries a Class 2B fit with an H7 thread limit, making it appropriate for standard-tolerance internal thread applications in both production and repair environments.

Key Features

• Thread forming design cold-works material for chip-free threading in blind holes
• Modified bottoming chamfer with 2 to 2.5 chamfered threads for threading close to hole bottom
• Powdered metal high-speed steel construction for improved toughness and wear resistance
• TiCN coating reduces friction and extends tool life in abrasive and hard materials
• H7 thread limit and Class 2B fit for standard-tolerance internal threads
• Right-hand thread direction, 5/16-18 UNC specification

Compatibility

Rated for use in alloy steel, aluminum, carbon steel, die steel, hardened steel, and stainless steel as stated in the manufacturer specifications. Suitable for 5/16-18 UNC blind hole threading applications requiring a Class 2B fit.

Installation Notes

Thread forming taps require a properly sized forming tap drill hole, which is larger than a standard cutting tap drill — consult the tap manufacturer drill chart for the correct pre-drill diameter before use. Use appropriate tapping fluid or cutting oil for the workpiece material; dry tapping is not recommended for steel applications. Secure the workpiece and use a rigid tapping fixture or CNC tapping cycle with synchronous feed to avoid tap breakage. This tap does not have coolant-through capability, so external lubrication must be applied at the cutting zone.