Abstract: An actuator assembly for dynamically or manually positioning a dome die and clamp ring of a can bottom former assembly. The actuator assembly is also usable for other purposes where accurate and repeatable adjustments in position are needed. The actuator assembly may include an anchor member and at least one torsion rod having a torque end and an actuation end, with 2 bends at or near the actuation end, such that a torque applied to the torque end creates a substantially linear actuation force at or near the actuation end of the torsion rod.