Hertel K008397AS 5/16-18 Unc Straight Flute Tap 4 Flute Hss

Product Description

The HERTEL K008397AS is a straight flute tap designed to cut 5/16-18 UNC internal threads in a wide range of workpiece materials. Built from high-speed steel (HSS) with a bright, uncoated finish, this tap delivers consistent thread quality in production and maintenance applications. The taper chamfer eases entry into the hole and distributes cutting load across several leading threads. With four flutes, a 1-1/8 inch thread length, and a 2-23/32 inch overall length, it fits standard tap handles and machine tapping chucks. The H5 thread limit holds a 2B class of fit, making it suitable for general-purpose fastener threads across ferrous and non-ferrous materials.

This tap is used in machine shops, maintenance facilities, and field service environments where 5/16-18 UNC threaded holes are required. It suits through-hole and open-ended blind-hole applications where chip clearance is adequate. Machinists, toolmakers, and maintenance technicians install it in hand tap wrenches or CNC and manual tapping heads. It is commonly used in light fabrication, equipment repair, and general metalworking where standard inch-series unified threads are specified.

Key Features

• 5/16-18 UNC thread form with H5 thread limit for 2B class of fit
• Four straight flutes for chip clearance in through-hole and short blind-hole applications
• Taper chamfer distributes cutting load across 7-10 leading threads for smooth entry
• High-speed steel construction maintains edge hardness across a wide range of workpiece materials
• Bright uncoated finish for straightforward use with cutting fluid in standard tapping operations
• Right-hand thread direction, compatible with standard tap handles and tapping attachments

Compatibility

Designed as a standard 5/16-18 UNC straight flute tap for use in any tap wrench, T-handle, or machine tapping chuck accepting a 0.318 inch shank diameter.

Installation Notes

A licensed machinist or trained maintenance technician should ensure the workpiece is securely clamped and the tap is started perpendicular to the hole before applying torque. Always use an appropriate cutting fluid or tapping compound to reduce heat and extend tool life. For power tapping, verify the machine spindle speed is appropriate for the workpiece material and tap geometry. Back the tap out periodically to break chips and prevent binding in blind-hole applications.