Expert: Kenneth Saunders - 8/20/2009

Question
I have a grandfather clock named "Belvil" with a (I believe) Hermle movement. On the back plate it says FHS 481-053.
I has a beautiful Westminster chime but runs all too fast.
I have tried to adjust the pendulum, but even on the very last turn of the adjustment nut it gains approx 1.5 min/day.
My question:
Would changing the pendulum spring to a longer one be an idea to try? It seems that the spring is not original (file tracks). How long should the spring be (between pins)? It is now approx 2 cm.

Yours sincerely

Åke N

Answer
back plate also indicates the pendulum length in CM from the suspension post at the top of the mechanism to the nut at the bottom.  is this clock new to you? might be the wrong pendulum? try tape to hold  a few big washers or coins to the back side of the bottom of the pendulum disk
2CM is about right for the Suspension spring.