look at those big steel gears in it...imagine them with perhaps 6 big holes drilled in them. Or if you have a lathe, imagine them with a thin web connecting the full width center hub to the full with outer gear tooth area.
Also think about the outer casing, and figure out if you could replace it with four tubes made of aluminum (or even hard plastic, such as Delrin).
Also look at the AndyMark web page and see what parts are for sale for it.
http://andymark.biz/am-0145.html
there are lots of things you can do!