Please view these information tabs to learn more about replacing clock pendulum parts.
Clock pendulum components description
Altogether, this is a description of the clock pendulum parts and components. Please use this as a glossary of the parts to a clock pendulum assembly. Knowing the correct terms for the various pendulum parts is helpful when locating replacements. We are pretty adept at deciphering descriptions of parts however knowing the name is always something we welcome.
The clock pendulum
First, a clock pendulum includes the bottom rating nut and threads, the pendulum bob, and top hook. Additionally, these items are removable on wood stick pendulums only. Lyre metal clock pendulums do not have the ability to come apart.
Clock pendulum leader
Second, a leader is the part that the pendulum hangs onto when it is installed on the clock. It then in turn hooks to the suspension spring on the very top of the pendulum assembly. Naturally, pendulum leaders vary depending on the manufacturer of the clock movement and they can also vary in length as well as style. Sometimes there can be more than one type of leader for the same movement. There are also instances where we custom make leaders for customers.
Suspension spring description
The clock pendulum suspension spring is the short spring steel part on the very top of the pendulum assembly. Its purpose is to suspend the leader and pendulum in the air. Generally speaking, its steel spring like strips flex to let the pendulum swing back and forth with ease and momentum.
Clock Pendulum Components Complete
In summary, the clock pendulum components description includes the pendulum hanging on the leader and the leader hanging on the suspension spring. Put the complete pendulum assembly on the clock and it is ready to go. The next step is to put the clock in beat and run the clock to see how the time keeping is.
Leader and suspension
Replacing Lost Pendulum Parts
By and large, replacing a lost pendulum part from its assembly is a process. It is more complicated than just matching up the broken pendulum part. Certainly, narrowing it down requires a different method than just observation. The following text will guide you through that process.
The lost pendulum
First, identify the movement manufacturer. This is the beginning step to identify a lost clock pendulum. This is done by getting the movement numbers off of the back plate of the movement itself. That is to say, it will not be in the manual that came with the clock. Moreover it will also not be on any stickers or the clock case. Match the movement number here to find out who made the movement. Finally, proceed to the pendulum page. This is the first step in replacing a lost pendulum as well as replacing lost pendulum parts.
Lost pendulum leader
The leader hooks to the suspension spring. The suspension spring is located at the top of the movement. The pendulum hangs onto the leader. All or some of these parts are what you need to order to replace lost pendulum parts. Again, the order of the parts is the suspension spring, the leader, then the pendulum.
If the leader is missing, identify who made the movement. Use the above information to correctly identify the movement so it is possible to replace the pendulum part. The leader possibilities are narrowed down considerably upon knowing who made the movement. This makes things much easier when replacing lost pendulum parts. After knowing the manufacturer, match the information to a leader shown on this page. In the final analysis, visually inspect the pendulum hook style, the crutch on the back of the movement, and the suspension hook. Finally, compare the components of the clock to the options in that manufacturer category to figure out the best one. Replacing lost pendulum part can be tricky however with these descriptions the task should be less daunting.
The lost suspension spring
First know that style A is the very most common suspension spring style in existence. Check the top of the pendulum leader and if there is a double hook on the end it will be style A required for the clock. Generally speaking, style A3 is used for large grandfather units, A2 for grandmother and wall clocks, and A1 for mantle clocks. Suspension spring are one of the easier parts to ascertain when replacing lost pendulum parts.
The mechanical clock pendulum length
A pendulum clock without a pendulum is a shame for sure. Hence, getting the mechanical clock pendulum length correct does take some diving into the clock world. If you have no idea what pendulum it would take, this is a basic guide. Of course, this is a basic guide to narrow it down to the best pendulum for your clock. This will cover most situations, without special equipment to figure out the length.
The movement CM or PL stamp
On the back plate of the clock movement usually, there are some numbers and or letters for identification. Likewise, there may be an indication of how long the pendulum should be in the mix of these numbers. It may say CM or PL and this stands for centimeter or pendulum length. Subsequently, this would be the length where it should keep approximate time. Generally, this is measured in a few different ways usually dependent on country of origin.
Mechanical Clock Pendulum Length for German made movements
Most mechanical German made clock movements are easy to figure out the pendulum length. In essence, the numbers will let us know or the stamp will clearly state the CM or PL number. If it is German, keep in mind the CM length is not the actual pendulum length. Altogether, German units measure this length from the top of the clock movement, and this includes the three components of the pendulum all in one length, in centimeters. This length will include the pendulum itself, the leader that it hooks to, and the suspension spring on the top that the leader hooks on to, all in one CM measurement. To clarify, CM stands for centimeter and PL stands for pendulum length.
If no stamp try to convert
With no pendulum length stamped into the movement some added steps are involved. The numbers on the back plate will cross reference to the pendulum length required. The first step is to identify the manufacturer of the clock movement by using the movement numbers. The movement numbers indicate who actually manufactured the movement. Various clock retailers may have have their name stamped onto it, but the numbers are always true to the manufacturer.
Converting numbers to CM length
Moreover, some movements do not have an indication of the pendulum length on the back plate. The unit will have a number that would need to be found on this website first to find out what the correct CM length is for it.
Converted number example
Generally speaking, let's say that the movement has no CM stamp on the movement and only shows the number UW32319. Go to the identification page to look at the movement number examples. In this example, we see that it is a Urgos. Now it is possible to go to the Urgos page and find the number to see what the pendulum length is. In this example, the pendulum length would be 80cm, representing the full length with the size of the bob factored in.
German grandfather movements
Almost all grandfather clock movements are going to be German if made after 1950. The first thing we need to do is get the numbers off of the back plate of the movement. This is the only way, and we can't cheat by looking at the paperwork or clock case. It has to come right off the back of the clockworks. The manual and the sticker on the case is of no use to get the pendulum.
The American mechanical clock movement manufacturers referred to the pendulum length as a "drop". The drop is the length of the pendulum from the hand shaft all the way down to the bottom of the pendulum rating nut threads. It is a different way of measuring the pendulum length then the German made way. Both ways are based on the smallest bob diameter bob. If the bob is larger or heavier, the length would be longer than what is stamped.
If everything fails for one reason or another, the best chance for a pendulum is the wood stick style. This is the only style of pendulum that can be easily modified because you can chop it. These types of clocks are usually antiques, or of Asian origin, and information such as pendulum length is simply not available. Sometimes it takes a good guess on where the manufacturer intended to have the bob sit.
To do it this way, you only need a pendulum with a stick that is way too long to begin with. Chop it, try it, chop it, try it. Each time your slow, cut an inch and half off of the sticks length and hang it back on. It will only take a couple of times, and if you start way too long you can always go shorter.
Clock makers method for Mechanical Clock Pendulum Lengths
There is another way, its called setting the beat rate. This is a more involved way and usually just done by clock makers. It involves a beat detecting device that counts out the beats per hour, or the beats per minute. To do this, first you would need to know what the beat rate is supposed to be for that particular movement, and then keep adjusting the pendulum length until you have it keeping time. There are cell phone apps out there these days that will tell you the beat rate and the cell phone will listen and tell you if the clock will keep time with that pendulum. You go longer or shorter until your phone says the beat rate is set.
Contacting us for help with Mechanical Clock Pendulum Lengths
Please email the movement numbers from the back plate, and explain what part is needed. The email address to send this information is [email protected] Pictures are welcomed but not required. If emailing pictures please include the back side of the clock movement where the markings are.
Timing a mechanical pendulum clock
Timing a mechanical pendulum clock is all about the overall pendulum length and rarely has anything to do with the movement itself. A mechanical clock is easy to time providing you have the correct pendulum. When the pendulum is correct for that particular movement it will hang on the leader and keep approximate time. The fine timing can be done only with the pendulum adjustment located at the very bottom. At the bottom of the bob is some adjustment threads and a nut. To turn the nut one way raises the bob and the other lowers it. A shorter pendulum will make the clock run faster. A longer pendulum makes the clock run slower.
Fine timing the clock
If the clock is timing slow, raise the pendulum bob by turning the nut at the bottom of the bob. If the clock is fast, do the same but raise the clock's pendulum bob instead. One full turn is somewhere around 1-2 minutes a day faster or slower.
If there is no more adjustmentIf the bob is all the way up and its still too slow or fast, you can shorten either the pendulum or the leader it hangs on to correct.
A lyre pendulum that does not keep time with the bob all the way adjusted will need its length altered. You can alter the overall length by the pendulum itself or the leader it hangs onto. The leader is about 5 to 7 inches long and engages with the crutch on back of the movement. The leader is the part that the pendulum top hook will mount to. It is possible to shorten or lengthen the pendulum leader to put the clock in time range with some solder if needed. 1 3/4 inches is a good measurement to make one of these longer or shorter as needed, as this is the length of the threads at the bottom of the bob. So it will give a full timing adjustment range all over again and can go up or down as needed.
German pendulum length CM stamp
The pendulum length is overall and not just the pendulum itself. These German units measure there pendulum lengths from the top of the movement and all the way down. This will include the suspension spring, the leader and also the pendulum itself. This is based on a 4 1/2 inch bob diameter. Of course the larger the bob, the longer it will be beyond that CM stamp measurement.
Used to keep time, now does not
If the clock kept time in the past but now does not, it means a worn gear. The escape wheel is worn and it is advancing more than one tooth at a time. The escape wheel alone would be hard to find, and hard to replace both. The entire movement would be disassembled to replace this worn escape wheel if there is another one found that will work. The cost of having this done would be the same price as a new movement. There is no such thing as having a repair on a clock movement being better than a new movement.
The price would be about the same for a complete overhaul or a brand new one. First see if the clock movement is in production and available new. We do this by getting the numbers off of the back plate of the movement itself, right off of the brass. Please email and we will check the availability and quote for the new one. If the movement is not in production anymore, then a movement restoration is the only option. The movement can be shipped to Clockworks Attn Repair department for a beautiful restoration.
Mechanical Pendulum Clock Timing Issues - Conclusion
Fine timing of the clock is easy as you can see. If the clock kept time in the past and now too fast, its time for a new movement and has nothing to do with the pendulum. A worn escape wheel is most likely the cause and a new unit would be less cost then a repair.
Suspensions are the top most portion of the clock pendulum assembly. Suspension spring style A is the most common that would be needed.
Pendulum top hooks to replace broken tops or a new pendulum creation. Most offered are for wood stick style clock pendulums.
Rating Nut and Threads
A threaded rod with its rating nut. Is installed into the bottom of a wood stick pendulum by threading it into a pilot hole drilled into the wood.
Lyre Rating Nut
This is the size rating nut for most of the Lyre pendulums for German units. Turn this nut as to move the pendulum bob UP will speed time up.