Osg 1405002808 Thread Forming Tap 5-40 Unc Bottoming

Product Description

The OSG 1405002808 is a thread forming tap in the EXOTAP VP-NRT series, designed for cold-form threading in blind holes. Unlike cutting taps, it displaces material rather than cutting chips, producing stronger threads with no swarf to clear. Built from powdered metal high-speed steel and finished with a TiCN coating, it handles demanding materials including alloy steel, stainless steel, hardened steel, carbon steel, die steel, and aluminum. The 5-40 UNC thread profile with a bottoming chamfer of 1 to 1.5 threads allows threading close to the bottom of a blind hole. Overall length is 1.9380 inches with a tapping depth of 0.6260 inches.

This tap is suited for precision machining and fabrication shops working with small-diameter fastener threads in blind-hole applications. The 5-40 UNC size is common in instrument work, electronics assemblies, and light mechanical components where thread integrity and close-tolerance fitment are critical. The H5 thread limit and Class 2B fit make it appropriate for standard commercial tolerance applications. It is used with CNC tapping centers, drill presses, and manual tapping setups where controlled feed rates can be maintained.

Key Features

• Thread forming design displaces material rather than cutting, producing stronger threads with no chips in blind holes
• Powdered metal high-speed steel construction for consistent grain structure and wear resistance
• TiCN coating reduces friction and extends tool life across a broad range of workpiece materials
• Bottoming chamfer (1 to 1.5 threads) allows threading to within a minimal distance of hole bottom
• H5 thread limit with Class 2B fit for standard commercial tolerance requirements
• Right-hand thread direction, no coolant-through requirement

Compatibility

Compatible workpiece materials include alloy steel, aluminum, carbon steel, die steel, hardened steel, and stainless steel (material application codes P, M, N). Designed for blind hole threading applications requiring 5-40 UNC right-hand threads.

Installation Notes

Thread forming taps require a specific forming tap drill size — consult a forming tap drill chart for the correct pilot hole diameter before use, as it differs from a standard cut-tap drill size. Ensure proper lubrication or tapping fluid is applied for the workpiece material, particularly with stainless or hardened steel. Secure the workpiece fully and use a tapping fixture or synchronized CNC feed to prevent tap breakage on this small diameter. Inspect the tap for wear or distortion regularly, as overloading a tap of this size can cause breakage without visible warning.