Fashionable Watches

Big Ben: Making sure the Great Clock strikes on time

Big Ben: Making sure the Great Clock strikes on time

Keeping Big Ben striking on time>>Parliamentary clockmaker: I am another one
of the clockmakers at the Palace of Westminster. Not only do we come up here three times a
week to wind it, three times a week we have to do a time check. And what we have to do, we have to phone up the Speaking Clock, take an accurate reading on the stopwatch, then go up and listen to the bells strike,so that’s what I’m going to do now. [Clockmaker picks up the telephone, rings
the speaking clock, listens and replaces the telephone] Now we have an accurate time reading. All
we have to do now is compare it with the first strike of Big Ben. [Clockmaker leaves the room and climbs a staircase
to the belfry] What you’re going to hear is, about twenty
seconds to the hour, the quarter bells will ring out sixteen notes,then there’s a pause
of about seven seconds and then the first blow of Big Ben is actually the time signal,
so we check to see how accurate we are. We’re allowed plus or minus two seconds. [Big Ben starts striking]>>Parliamentary clockmaker: Should be, shall we say three minutes, and
we have got three minutes and twenty-one hundredths. Now we’ve got the accurate time reading,
what we do now is we enter it on to a log, which has been going for about the last hundred
years. we put barometric pressure on the log, we
put the temperature of the Clock Room,we make a record of how many corrections and how much
is actually on the pendulum, then we sign it and put the date and the time
on the log.Barometric pressure is 1016, we put what time we did the time check (ten o’clock), we sign it. The temperature in the Clock Room is 64. We have got nine pennies on the record, carry
that over and we just put it on the chart itself, that
we’re less than half a second slow. How is the time adjusted if the clock is fast
or slow?>>Parliamentary clockmaker:This is an old
English, pre-decimal one penny piece that we use to adjust the time.We have a little stack of coins on the pendulum shelf and by placing one more penny on the pendulum, it speeds up the timekeeping by two-fifths of a second in 24 hours.This is how we can get it so accurate. So, if I place one on, in 24 hours’ time,
it will be two-fifths of a second faster; take one off, two-fifths of a second slower. For more information about the Clock Tower
and Big Ben, visit

Reader Comments

  1. That makes me curious if anyone has accidentally dropped any of those old coins down into the pendulum chamber. Also, I wonder if there would be a more efficient way of keeping the clock's accuracy in check because it looks like with a swinging pendulum, some of the coins could fall down into the pendulum chamber. I may not be British (I'm American) but I definately think this clock is awesome and I hope it keeps ticking for many years to come.

  2. A machine is only as efficient as those who take care of it, but we don't have to worry about that with a fine crew taking care of this clock which in my opinion is a great British icon.

  3. Bleibt das Schlagwerk nach dem Schlag etwa auf der Glocke liegen? Klingt irgendwie nicht so, als könnte sie frei nachklingen, oder kommt das nur bei diesem Video so rüber?? Klärt mich mal auf!

  4. Nein, das ist nicht so, man meint es nur. Über dem Hammer siehst du ja noch eine Stange, und da sind 2 Gummis dran, so änlich wie Türstopper, und die halten den Hammer ca 5-10mm von der Glocke weg, also man kann es nicht erkennen!

  5. @BexterzzNY The coins add a tiny bit of weight to the pendulum, increasing its momentum and causing it to swing marginally faster.

  6. @denelson83 The talking clock uses the same time signal as the MSF signal. I'd guess it's just a more convenient way of doing things. You're still going to have to go up there with a stopwatch whatever you do, so to take ten seconds to get the time reference from the talking clock makes sense to me.

  7. @BartBassist Let me expain why adding weight actually increases the rate of the penculum swing. It's because the weight is being added above the "center of oscillation" of the pendulum. The calculations are complex but the idea is simple… the same weight added below the center of occilation would slow the pendulum – at the bob for instance. But where the weight is being added is very close to the top.

    Nice series of videos. Thank you.

  8. I used to know someone whose father, in the 1920's, was in charge of maintenance of all the public clocks in London, including the one associated with Big Ben. Unfortunately, he died in 1929.

  9. Calling up the talking clock 3 times a week? Cor… I bet their phone bill is a lot, the talking clock costs a bloody fortune.

  10. @kensai7gr Aah you see that's the thing. It's not actually accurate at all when compared to an atomic clock, but 'we British' love things that are fallible – I mean what other country could get away with producing both the Reliant Robin and the Spitfire.

  11. @fmBillion Hehe I suspect BT (or whoever runs the speaking clock nowadays) and the management of the Houses of Parliament have probably struck a deal somewhere along the lines of history.

  12. @Logixmaster Someone whose practised can react to a familiar sound within 0.10 of a second, I imagine someone whose *really practised* can react to a sound within a smaller time frame. However, it will be insignificant by the time the sound has travelled 180ft to the ground (which is where a majority will hear it) – as the sound wave will have only travelled 126 feet in that time.

  13. ….and yes I know it should be 'who has' rather than whose but my writing style changed half way through writing this and didn't proofred wot I had writted.

  14. Just as well he didn't knock the pile of coins off at the end !
    Why ring the speaking clock for the check, why not use a digital radio controlled clock to get the exact time?

  15. pigeonhouse is right but when you set a stopwatch to the speaking clock you don't react to the third pip, you anticipate it based on the first two so your accuracy in starting the watch is more like 0.005 seconds if you've got good rythm. Plenty good enough for a pendulum clock time check.

  16. It has to be pretty accurate, as there are still people who set their watches in accordance with the chiming of Big Ben itself…and some will make a nasty call to the clock management if it is off…

  17. And end up in hospital after, just tried that & it hurts….Skullcandy in ear headphones £10 from HMV with bass boost plugged into a Lenovo Ideapad with HD Realtek HD Audio & SRS Premium Surround Sound enhancement = FUCKING HELL THATS LOUD!!!!

    I dare someone to plug their pc into a surround sound system wack it up full blast, the bigger the speakers the better & not shit themself…or better still hook it up to a shopping centre PA system & do the same!!!

  18. He put the penny down for a couple seconds for demo purposes so now the clock is gonna slowly register in time and make the month of february longer in the year 3448 or somn like that… XD ah computation..

  19. I was outside the Parliament House when Big Ben struck noon, and I must say that it was one of the best clock strikes I've ever heard

  20. this is how it goes. Bell: Big Ben. Tower: Elizabeth tower. Clock: The great Westminster clock

  21. Big Ben is the sound of London. Old, glorious sounding, beautiful landmark of Western civilization. He's been ringing in the hours for London since the days of Queen Victoria, and he is magnificent. God preserve Britain.

  22. May God forever bless Queen Elizabeth II and the special relationship between the U.K. and the U.S., which was so critically important during the Second World War, in the defeat of the Nazis and in the liberation of Europe. May Big Ben and the Westminster clock chime on forever.

  23. I know this was posted almost a decade ago, but do they really still phone a speaking-clock to get the correct time to set with? Also HOLY CRAP when the Great Bell tolled!

  24. The clock movement is obsolete it should be sent to a museum. The clock hands over the beautiful facade and its iconic chimes should be driven by a step motor whose pendulum control are the oscillation of a hydrogen maser adjusted for leap second

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