A valve includes a shaft having threads along at least a portion of a length of the shaft. A travel limit member (e.g., a coil spring, a washer, etc.) is disposed within one or more of the threads. The travel limit member may comprise a coil spring configured to be movable within the threads along the shaft when the shaft is rotated relative to the coil spring. The coil spring is configured to be operable for providing: a safety stall or hard stop for a fully open position of the valve when the coil spring is within the top thread and/or runs out of the threads after having traveled upwardly along the shaft within the threads; and a safety stall or hard stop for a fully closed position of the valve when the coil spring contacts a stop after having traveled downwardly along the shaft within the threads.