Since the gear blank was originally a flat plate, weight reduction % can be calculated by subtracting the area of the drilled holes from the area of the undrilled gear and dividing by the area of the undrilled gear.

However, I have a background in machining and have some concern about drill press safety when drilling large 3/4 holes in .125" tempered aluminum. This work should really be done by a trained machinist in a machine shop. In addition, most modelers don't even own a 3/4" dia. drill.

If we don't have any luck with the CF gear route, then I may take a "cut" at it in the near future. My spare time right now is almost nonexistent.

Bruce