The following is a summary of the main facts about the clock, tower and bells.
- The total height of the tower is 316 feet
- The height of the belfry is about 200 feet
- There are 290 steps to the clockroom and 340 to the belfry
- The quarter chiming bells are in the key of F
- The hour bell (Big Ben) is note E and weighs 13.5 tons and has a maximum diameter of 9 feet
- The hammer of the hour bell weighs 4 cwt.
- The four quarter bells weigh (in order of size) 1 ton, 1.25 tons, 1.6 tons and 3.5 tons
The Dials and Hands
- The diameter of each of the four dials is 23 feet
- Each dial contains 312 panes of glass (and we are happy to dispel the myth that there are 365, one for each day of the year, yes, we've counted them!)
- 28 bulbs are used to light each dial from behind
- The hour hands are 9 feet long and weigh 0.8 cwt.
- The minute hands are 14 feet long and weigh 2.5 cwt.
- The Roman numerals are 2 feet high
The Clock Movement
- Three train flatbed movement with Grimthorpe's double three-legged gravity escapement and two-second pendulum
- The frame of the movement is about 16 feet long and the entire machine weighs 5 tons
- The driving weights weigh 2 cwt. (going), 1 ton (striking) and 1.25 tons (chiming)
- The chiming and striking trains have been wound by motor since 1912 but the previous hand winding took two men 5 hours per train
- The going train is still wound by hand which takes less than 30 minutes
- The overall length of the pendulum is about 14 feet and it weighs 2.5 cwt.
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