A motorized anti-backlash linear actuator comprises a motor; a hollow shaft that is rotated about a central axis by the motor, an anti-backlash nut that is nested at least partially inside the hollow shaft; and an externally threaded rod or lead screw that engages with the anti-backlash nut such that the rotation of the hollow shaft and the nut imparts a linear motion to the rod that is substantially free of backlash. Nesting the anti-backlash nut at least partially within the hollow shaft provides greater stability to the actuator, and permits high speed operation. A mechanical element, such as a nut or a bushing, comprises a first cylindrical element comprising a first material; a second cylindrical element comprising a second material, the second cylindrical element having a different coefficient of thermal expansion relative to the first cylindrical element, the second cylindrical element being disposed inside of and in contact with the first cylindrical element; and at least one interlocking structure at an interface between the first cylindrical element and the second cylindrical element to prevent the second cylindrical element from separating from the first cylindrical element under thermal effects. The mechanical element can be a plastic nut secured to the interior of a hollow shaft of a motorized anti-backlash linear actuator.