Hertel K010378AS85 Thread Forming Tap 5/16-18 Unc Bottoming

Product Description

The HERTEL K010378AS85 is a thread forming tap designed for creating 5/16-18 UNC internal threads in blind hole applications. Unlike cutting taps, thread forming taps displace material rather than cut it, producing stronger threads with no chips to clear. This tap is manufactured from high-speed steel and coated with TiCN for extended tool life and reduced friction. It carries a 2B class of fit and an H5 thread limit, making it suitable for standard tolerance threading work. With an overall length of 2.7188 inches and a 1.125-inch thread length, it is sized for typical machine tool setups in production and repair environments. Licensed machinists and tooling technicians are the primary users.

This tap is built for blind hole threading in ferrous and non-ferrous metals where chip evacuation is a concern and material flow forming is preferred. The bottoming chamfer geometry, with 1 to 2 chamfered threads, allows threading close to the bottom of a blind hole. It is well suited for use in CNC machining centers, drill presses, and tapping machines in industrial, maintenance, and job shop settings. The TiCN coating improves wear resistance compared to uncoated high-speed steel, extending service intervals in moderate-volume production runs.

Key Features

• Thread forming design displaces material to create chip-free blind hole threads
• TiCN coating reduces friction and extends tool life versus bare high-speed steel
• Bottoming chamfer allows threading to within 1 to 2 pitches of hole bottom
• H5 thread limit for consistent 2B class of fit tolerances
• Right-hand thread direction for standard machine spindle compatibility
• No coolant-through requirement simplifies setup on standard tapping equipment

Compatibility

Designed as an OEM-style replacement or direct-use thread forming tap for 5/16-18 UNC blind hole applications in machine shop and industrial maintenance environments. Fits standard tap holders sized for a 0.318-inch shank diameter with a 0.238-inch square drive.

Installation Notes

Thread forming taps require a larger pilot hole diameter than cutting taps — consult a thread forming tap drill chart for the correct forming drill size for 5/16-18 UNC before drilling. Adequate lubrication or cutting fluid is required to prevent galling, particularly in steel or stainless materials. Ensure the workpiece is securely fixtured and the tap is properly aligned to the hole axis before engagement. Inspect the tap for wear or damage before each use and replace when torque requirements increase noticeably.