a machine for stamping characters in multiple rows on a workpiece is disclosed . the machine includes an impact head assembly mounted on a transversely slidable carriage , the impact head assembly being adapted for reciprocating movement perpendicular to the path of that sliding movement . a rotating stamping wheel is mounted in the impact head assembly and has a plurality of character stamps mounted on its periphery . means are disposed in the impact head assembly for moving the stamping wheel to a plurality of selected positions along its axis of rotation .