The Great Clock of The Palace of Westminster. Maintained by Thwaites & Reed for over 30 years
Big Ben
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Article 1 Time Keeping
Three times a week a clockmaker climbs the 300 steps of the stone spiral staircase which winds its way inside the clock tower. The House of Parliament of which the clock is a part, allow visitors to the clock, and special tours are available. If you had any desire to wind the clock by hand (which you would not be allowed) it would take you about 6 hours for each of the strike and chime barrels, say 8,000 turns of the handles, and then you would have to wind the going train. After that you face 300 steps going down in a spiral. In fact the clock is wound by a mixture of motors and by hand, and in addition to this work the clockmakers also make adjustments and lubricate the clock as daily tasks. The clock is very accurate and rarely varies by more than 2 seconds a day, usually it is exactly on time. Viewed from the ground, a 2 second variation is not visible because of the parallax distortion.Denison held firm views that most clockmakers make dials too small and out of proportion to the height of the buildings. He preferred a 10 to 1 ratio and the dials of the clock are 23 feet in diameter with 14 foot minute and 9 foot hour hands.Whilst a 2 second variation is not visible, a 2 second delay is audible if the clock struck at different times. An unusual feature of the clock is that Big Ben is struck on the hour. As the hammer weighs 448 lbs it takes a little time to raise it and then let it drop. Denison cleverly designed the strike mechanism so that the hammer is already cocked and ready to strike on the hour. All this lends to superb timekeeping.
In May 1859 the most famous clock in the world was set to work, driving the enormous hands and mechanisms needed to set in motion the tones of Big Ben which is the hourly strike bell. Easily recognised by its unique shape and sound and its reliability, the Great Clock which everyone calls Big Ben was looked after by a team of up to 8 expert clockmakers from Thwaites & Reed for over 30 years.The designer was Edmund Beckett Denison who worked with F. Dent the clockmaker until old Mr. Dent died in 1860. Denison deserves credit because for almost 16 years there had been arguments between clockmakers and bell founders all fighting for the honour to make the most expensive and accurate clock at that time. Ironically Thwaites & Reed were excluded from the work, but today have outlived all our rivals but ceased to officially maintain the clock in 2002 when two clockmakers transferred to the Houses of Parliament (the second time in our history we have ceded control to the Government).