Reply To: French Clock Pendulum Length Calculator. Home › Forums › Hints, Tips and Tricks › French Clock Pendulum Length Calculator. › Reply To: French Clock Pendulum Length Calculator. May 8, 2013 at 10:19 am #53559 willofiamModerator Topics Started: 75Total Posts: 1437 excellent info Paul, just what I needed, your the best!!!!! William willofiamReply To: French Clock Pendulum Length Calculator.