If somebody has enough common sense to keep his fingers out of the ring gear/pinion junction, a 20:1 ratio should give him plenty of control over the engine's position, and if he doesn't, he probably shouldn't be handling anything more dangerous than a potato in the first place! I guess I could incorporate a small sheet metal shroud over that area.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!