Regulating Your Longcase/Grandfather Clock For Running Speed
To do this you adjust the regulation nut which is at the bottom of the pendulum. If you turn the nut to the right you will speed up the clock and if you turn it to the left you will slow down the clock. You should hold the pendulum shaft with one hand with a little downward pressure and adjust the nut with your other hand so you do not unhook the pendulum.