Sassylass, the steel that goes from the pillar to the slide looks like it may be the control lever for the motor, though different from most I've see. Leaving the machine unplugged, if you put the right end of the lever into the hole at the right side of the case can you feel a bit of spring tension as you push the bottom of the lever to the right?
My28 is a blackside crinkle finish , newer than yours. currently ( no pun intended) converted to handcrank