Abstract: A drill for stack drilling comprises a drill body, a central cutting insert, and a peripheral cutting insert. The inserts have active cutting edges arranged such that the drill successively cuts radially outwardly from the center of the drill in order to avoid the formation of break-out slugs. The active cutting edge of the central insert has three cutting edge portions forming obtuse angles with one another. The radially innermost one of those cutting edge portions is shorter than each of the other two cutting edge portions.

Abstract: The invention relates to a short-hole drill and a cutting insert therefor, for drilling of metallic work pieces. The drill comprises a drill shank with two chip flutes formed therein and with two cutting insert sites and two mainly rectangular cutting inserts having mutually identical shaping. The cutting inserts are accommodated in the cutting insert sites and secured thereto by means of lock screws such that the broken non-active cutting edge abuts against a broken support surface in each cutting insert site while the active cutting edge projects axially forwards. The cutting insert which is arranged radially outermost is inclined such that it determines the size of the bore while the longitudinal axis of the other cutting insert is arranged parallel to the center line (CL) of the drill. The distance between the outermost parts of each cutting edge is longer than the shortest distance between the long side surfaces of the cutting insert.