Hertel K011078AS Straight Flute Tap 5/16-18 Unc Bottoming Hss

Product Description

The HERTEL K011078AS is a straight flute bottoming tap designed to cut 5/16-18 UNC internal threads in pre-drilled through or blind holes where full thread depth close to the bottom is required. Manufactured from high-speed steel with a bright uncoated finish, this tap delivers a 2B class of fit to standard tolerance, making it suitable for general-purpose threaded fastener applications in metal fabrication, maintenance, and repair work. With 3 straight flutes and an H5 thread limit, it is well suited for use in softer metals and materials where chip control is manageable. The overall length is 2-23/32 inches with a thread length of 1-1/8 inches.

This tap is intended for threading operations in machine shops, maintenance facilities, and production environments. Straight flute geometry makes it a practical choice for through-hole and short blind-hole applications in aluminum, mild steel, brass, and similar materials. The bottoming chamfer design allows threading to within a few pitches of the bottom of a blind hole, making it a common second or finishing tap in a two-tap or three-tap sequence. It is typically used in manual tap wrenches, tapping fixtures, or low-speed machine tapping setups.

Key Features

• Bottoming chamfer allows threading close to the bottom of blind holes
• 5/16-18 UNC thread form with 2B class of fit for standard tolerance fastener applications
• High-speed steel construction provides durability across a range of common workpiece materials
• 3 straight flutes suited for softer metals and materials with manageable chip loads
• H5 thread limit ensures consistent fit within the 2B tolerance range
• Bright uncoated finish, right-hand thread direction, no coolant-through feature

Compatibility

Designed as a standard replacement or additional bottoming tap for any setup requiring 5/16-18 UNC internal threading at 2B class of fit with an H5 thread limit.

Installation Notes

Threading operations should be performed with proper cutting fluid or tapping compound applied to the tap and workpiece to extend tool life and improve thread quality. Ensure the tap is aligned perpendicular to the workpiece surface before beginning the cut to avoid cross-threading or tap breakage. In a blind-hole sequence, use a taper or plug tap first and finish with this bottoming tap. Follow applicable shop safety practices and machine lockout procedures when tapping on powered equipment.