Rather than just design another version of the big gear project but with an involute gear I've decided to create a slightly more complex gearbox. The gears here have eight, twenty one and thirty teeth. The ratio of input to output speed will be 1 : (30/8) x (21/8) = 1 : 9.84375 in other words, the small gear on the right will spin almost ten times as fast at the large gear on the left.

Box design next.