How Much Drive Weight Does My Clock Need? Factors

Hello Clayton,

My grandfather is now reading your explanations and has a question about the weight that is needed for the copper weights.  Is it necessary that these weights are approximately 6 pounds and 1 pound (we don’t know the exact needed weight of the small contra weight) or can this also be different weights in the same equation? For example; 3 pounds and ½ pound.

Kind regards,
Genesis by Clockmaker Isaac Neuman (demonstrating weights)

Aloha Nick, in the Genesis design there is no weight in the small counterweight tube.  The Genesis counterweight tube remains empty.  The purpose of the counterweight tube is only aesthetic, allowing the clock to look balanced, and to keep the wind cord from tangling.

The large tube is the weight tube that contains the mass that drives the clock.  

As the clock runs, the drive weight slowly lowers toward the floor.  The Genesis is then rewound by pulling down on the counterweight tube while gently lifting the drive weight tube back up toward the clock.  As the clock runs the drive weight goes down, and the counterweight goes up toward the clock again.

The exact weight necessary to drive any clock is to be determined at the end of the build, and depends upon the craftsmanship that the builder has put into the clock.  Poor craftsmanship leaves excess internal friction in the clock's train, and good craftsmanship leaves much less internal friction.  It is the amount of internal friction left in each individual clock that determines the actual drive weight.

The Genesis's recommended "six or seven pounds" of drive weight is actually excessive.  My Genesis runs on about three pounds of drive weight, but because Genesis is a beginners clock, I expect there may be room for some improvement in craftsmanship, and I want everyone to be able to hear their clock tick.  A well made Genesis should run easily on half of the recommended drive weight, with zero pounds in the counterweight tube.

If a builder wants to know how much drive weight his clock takes to run, I have him add enough drive weight to get his clock running and then put a scale on the floor under the drive weight.  When the clock stops with the drive weight on the scale he can simply read the number of pounds of drive weight required off of the scale.  I then recommend adding back an additional ten percent of that amount to keep the clock running during humid days.

BTW, be sure to read over the section on "Depthing" in my FAQ's to help find and eliminate any residual internal friction that may be left in the clock's train.  

Three of the very best things a builder can do to get their clock running nicely is 1) following the Depthing procedure, 2) not get any finish on the tooth surfaces of the gears, and 3) not add any brass tube bushings unless specifically called for in the plans.

Enjoy!  Aloha.  Clayton