Abstract: An improved actuator stem and actuator design are provided that greatly increase the accuracy of actuator type precision operations, such as surface mounted electrical component placement, die and attach tooling movements, and tape and reel part storage tooling. The actuator includes a housing having an inner surface and containing a first opening, a stem having a first end, an axis passing through said first end, and a cross section perpendicular to the axis having at least one edge. The stem is slidably disposed in the housing with the first end extending through the first opening substantially parallel to the axis. The stem is actuated along the axis by conventional methods, such as a spring. A portion of the inner surface conforms to a portion the cross section of the stem so as to prevent the stem from rotating about the axis. In a preferred embodiment, the stem has a D-shaped cross section perpendicular to the stem axis over the entire length of the stem in the direction of the axis.