An engraving head (18) supporting a cartridge-type diamond stylus (22) is provided having a trapezoidal cross section for facilitating positive positioning of the stylus (22) within the engraving head (18). In another aspect of the invention, a self-aligning shoe tool (26) includes two omni-directional convex diamonds (68, 70) located in spaced relation to each other and mounted for pivotal movement relative to a support arm (62) to facilitate alignment of the shoe tool (26) relative to a cylinder surface to be engraved. In yet another aspect of the invention, a burr cutter (28) includes a curved cutting edge (126) to facilitate tangential contact with the cylinder surface.