Abstract: A reduced pressure reaction chamber allows rotation of a workpiece, and translation of the workpiece along the axis of rotation, using a sealed rotate and translate actuator. The reaction chamber has rigid walls, and is particularly suited to reduced pressure systems. The actuator includes a shaft coupled through the wall of the chamber by a vacuum rotary feed-through mechanism. A sleeve is mounted over the shaft and coupled to the shaft by means of threads, and shaft seals, which provide a frictional coupling between the shaft and the sleeve. Due to the frictional coupling, the sleeve attains the same rotational velocity as the shaft. A clutch is provided, which engages the sleeve when linear translational motion is desired. The difference in rotational velocity of the shaft and the sleeve is translated into linear motion by the threads. The shaft seals, in addition to providing the frictional coupling, seal the actuator, and reduce contamination caused by such mechanism.