I just had an email in from Jonathan, a fan of the blog here. He asked me to give me some info on his clock, which I duly did, but he also mentioned he was using extra weight on the pendulum bob to try and slow the clock down a bit.
Now…..thats not the way to do it. It works for Big Ben which until recently was ajusted for timekeeping by placing penny coins on the weight and therefore slowing the clock down a fraction. Yes, you heard right, Big Ben has been keeping good time for all these years because there is a man putting coins on its pendulum which is about the size of two large buckets and would probably need two or three people to lift it.
I rather liked this way. Now its going to change with the refit but I dont think its money well spent. They should have just left it the way it was and kept on employing a regulator to make penny weight manual adjustments. If they put a B£%$$ computer in it I will personally break in and pour water into the keyboard. I believe that clock should be kept entirely hand made and manually regulated because it is a reflection of our awesome country and its history or engineering innovation and skills. Don’t get me started about the Chinese running our 5g telephone network. Perhaps I will blog on that once china has invaded us with ease because they have turned off all our phones capabilities other than its ability to broadcast our location to anybody who wants to war us up. There is a huge “I told you so” coming if it happens.
So how do you regulate your clock (regulate is the term used to descibe messing around with various elements of the clock to adjust its time keeping). Well its fairly easy.
Im going to try and describe this without pictures for the meantime, so, firstly look at your pendulum. You will notice what is probably a square nut stopping the pendulum bob (disc) falling off the pendulum. That nut is there specifically to enable you to set how fast or slow the clock runs. If you screw it anti clockwise (looking from above) then the clock will run faster because the pendulum will swing slightly faster. You cant see this – you just have to know its happening. If you are struggling with this concept just think about playing conkers when you were young. If you used a short string the conker swings quickly back and forth. If you use a long string it sways back and forth much more slowly.
There is a sweet spot for the bob on the pendulum that will result in near perfect time keeping providing the clock is kept within a few degrees of the ambient temperature at the time you are regulating. Believe it or not you clock will run a few seconds slower on a hot day because the metal and therefore the pendulum rod will expand and become longer. The longer the pendulum (or to be more accurate its centre of gravity) the slower it will oscillate and the slower the clock will run as a result.
The method for this bob based regulation is as follows. This method is for clocks running fast but is the same (but opposite) for running slowly.
- At a given time of day set the clock to the exact time (taken from a modern clock or good watch) and then set it going. The next day you will see it is probably running a litte fast or slow. Make a note of how much faster your clock is running than it should e.g. 2 minutes per day.
- Turn the screw on the end of the pendulum one complete turn anti clockwise. Then set the clock back to you watch time and run for another 24 hours.
- You will notice the clock is either running fast or less slow. You make a note of this change so that you know that one complete turn makes a difference of, lets say, 30 seconds per day.
- Mathematically calculate how many 30 seconds you need to add per day to achieve accuracy and then turn the nut that many times and run for another 24 hours. If you’ve done the maths right he clock should be, in our example here, no more than 30 seconds fast or slow.
- Once the clock is regulated to 30 seconds per day then you have to move to weekly regulation and quarter turns on the nut (which is why it is square). Exactly the same process applies for weekly as for daily regulation, its just that you run it for a week to exaggerate the time gain/loss and adjustments to the nut at the bottom can be as little as quarter or eighth (or less) of a turn.
Some of my customers grandfather clocks are the most accurate in the house and there is one I know of that gains a minute a year. These clocks were built for accuracy. Just because the mechanics can look somewhat chunky dont let that fool you into thinking that the clock cant be regulated to almost 100% accuracy. My grandfather clock runs more accurately than my 1962 Rolex and yours probably can too.
Regulation is not a service I provide. I will regulate any clock which goes over our bench to about 5 or 10 minutes per day. I then tell the customer how to regulate it themselves when I deliver or they pick up. Its great fun seeing how accurate you can get your clock and most of my customers are genuinely interested in doing a bit of assisted maintenance like regulation. Im more than happy to help them do this because…..because I just think if I sold somebody a car Id tell them where to put the oil, petrol and water. Its the same with clocks – I always try and get my customers into the mechanical aspects of their clocks because its so interesting and connects us directly with our science heritage and of course the long dead maker of the clock. Immortality is only theirs if you keep the clock in good order!.
Note that this method can be used for any clock; mantle, wall or standing. If the clock only has a short pendulum e.g. a mantle clock, then you need to work on regulation for some time and definitely do the weekly regulation after you have done the daily. Also be aware that clocks run at different rates depending on where they are wound up to. The fusee mechanism was developed to overcome this but most clocks dont have that so be prepared for a level of daily inaccuracy with the plus side being that by the end of the spring wind the clock should be accurate.
Lastly. If you have something you would like me to write about please email me. Ive covered a lot in this blog over the years, and while I could write forever on clocks, I want it to be interesting and relevant to what people want to know.