Selecting pendulum mass
  • I am aware that for an ideal pendulum, it doesn’t matter—the period is the same no matter how massive the bob is.

    Of course, real clocks are more complicated. A couple points I can name are that a heavier pendulum puts more load on the pivot (thus increasing friction) and accelerates less when receiving impulse.

    A heavy pendulum is called for when the escapement has recoil, but for a deadbeat escapement, which will tolerate a very wide range of pendulum masses, how does a clockmaker determine the optimum pendulum mass, e.g. for best timekeeping or lowest drive weight? Trial and error? Is there some rule‐of‐thumb?