Tool holder block and sleeve retained therein by interference fit

(canceled)

(canceled)

A hollow sleeve adapted to be mounted in a hole of a holder block to receive a cutter bit, comprising:

• a shank including a front end and defining a longitudinal axis, the shank including 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 rearward direction away from the front end, each surface section having longitudinally spaced front and rear ends;
• wherein the number of surface sections is three, consisting of a front surface section closest to the front end, a rear surface section farthest from the front end, and an intermediate surface section situated between the front and rear surface sections, each surface section having a longitudinal length substantially equal to one-third of a longitudinal distance extending from the front end of the front surface section to the rear end of the rear surface section and
• wherein each of the plurality of axially adjacent surface sections has a substantially spherical curvature, has a substantially parabolic curvature, or has a substantially elliptical curvature.

A holder block adapted to receive a hollow sleeve, comprising a body having a hole formed therein and defining a longitudinal center axis, the hole including at least one surface section which includes longitudinally spaced front and rear ends, wherein a portion of the at least one surface section situated between the front and rear ends is spaced farther from the axis than are the front and rear ends, and wherein the at least one surface section is non-planar.

(canceled)