The very well made mechanical stage is of a slightly different finish than the rest of the microscope, suggesting it was an addition, perhaps developed a bit later than the microscope itself. The mechanical stage is controlled by knurled knobs which have a hatched knurling as opposed to the simple unidirectional knurling of the other microscope controls. Movements are by diagonal racks and pinions. There is a spring on the right side slide clip to hold it against the slide, and the left sided one is curved with a slot in it. The mechanical stage attaches by registering its two holes(red arrows) on small pins on the bottom of the stage and is held in place by a single knurled screw in between the two pins, screwing up from the bottom through a third hole in the center (blue arrow). The slide for right-left motion is rectangular and for forward-backward motion is a dovetail. The quality of machining is very high, and the mating with the microscope very sound, suggesting this was a professionally made accessory. The fact that the case seems made to accomodate the microscope with the mechanical stage in place also suggests this was a factory addition. Although the two mechanical stage control knobs are covered with cross-hatched knurling, the center scew holding the mechanical stage in place from underneath has unidirectional knurling.