: Material HSS Color : Silver Tone pinched Speed Steel criterial 60 degree included angle precision import relief ended Specification : This listing is for a set of 5 HSS Center Drills Each drill has a relief end and is ground with a criterial 60 degree included angle The set includes 1 each of the succeeding sizes : # 1 with 3 mm body diameter & 1 mm drill tip diameter # 2 with 4 mm body diameter & 1.5 mm drill tip diameter # 3 with 6 mm body diameter & 2.5 mm drill tip diameter # 4 with 8 mm body diameter & 3.15 drill tip diameter # 5 with 12 mm body diameter & 5 mm drill tip diameter Usage : Center and spotting drills are traditionally used to make a conelike hole for a lathe center in order to make a starting point for a criterial twist drill, designed to prevent the twist drill from walking Used for producing center holds in components or work pieces with require machining between centers Package Included : 1x a set of 5 HSS Center Drills .