Patent attributes
A hollow sleeve is mounted in a hole of a holder block to receive a rotary cutter bit. The sleeve includes a front flange and a shank extending rearwardly from the front flange and defining a longitudinal axis. The shank includes an outer periphery having a radially stepped configuration, wherein an outer surface of the shank includes a plurality of axially adjacent surface sections that become successively smaller in cross-section in a direction away from the flange. Each surface section occupies one-third of the hole length. Each surface section has longitudinally spaced front and rear ends, wherein a portion of each surface section situated between its front and rear ends is spaced farther from the axis than are the front and rear ends. Each surface section has a generally longitudinally extending groove formed therein.