Abstract: An improved simple and low cost tamping system for a printed sheets compiling system directly driven by partial rotation of a reversible stepper drive motor driving a single molded plastic tamper drive unit. That tamper drive unit integrally includes a rigid radially extending portion rotatably driven by the drive motor, an elongate flexible member portion driven from one end by the rigid rotatable portion, and a tamper at the opposite end of the elongate flexible member. The elongate flexible member is slidably mounted in a fixed guides system to smoothly transition from an initial arcuate configuration to a final linear configuration to convert reversing partial rotational movement of the stepper drive motor into the desired substantially linear reciprocal sheet edge tamping movement of the tamper.