Provided herein is an apparatus including a loader configured to position a workpiece in a holding fixture. In some embodiments, the holding fixture includes an opening configured to removably receive the workpiece therein and hold the workpiece in a target position within the opening. The apparatus also includes position detecting means configured to translate a sensor to a predetermined location relative to the holding fixture and further configured to translate the workpiece by a predetermined increment relative to the predetermined location to position the workpiece in the target position.