Tip angle of 180° (flat) enables plunge boring of not only flat surfaces but also of non-flat surfaces (sloped surfaces, etc.)

Special flute shape reduces breakage or chipping of cutting flute to enable stable machining.

Special groove shape provides smooth chip discharge, eliminating problems due to chips.
 

http://www.mmc-hitachitool.co.jp//j/products/new/zpb/zpb_e.html