Check out this brief video from Kennamental Inc. showing a side-by-side comparison of an HSS tap vs. a solid-carbide tap. The video accompanies CTE's August cover story on selecting the right tap for different workpiece materials. The split-screen video demonstrates the significant productivity advantage of the first solid carbide tap specifically engineered for tapping steels.

Both the high performance TiN HSS coated tap shown on the left and the new generation solid carbide tap shown on the right were used to tap 1/2" deep through holes in 150 HB 4340 steel. Using a CNC machining center with synchronous tapping capability, the HSS tap was used at the recommended speed, 25 m/min (80 sfm) while the solid carbide tap was used at its recommended speed 100 m/min (320 sfm). In 30 seconds of tapping, the carbide tap produced 36 holes versus 12 by the HSS tap, a 3x improvement in productivity.

The solid carbide tap is manufactured from a patented coated carbide grade developed by Kennametal for tapping steel. The design consists of a precision cylindrical shank, a left-hand spiral flute (RH thread) that directs the chips ahead of the tap in through holes and internal cooling. Other new carbide tap designs are available for blind holes in steel as well as tap styles and grades for cast iron and aluminum. Video courtesy Kennametal.