The below pendulums are for German post WW2 clocks. The four clock movement manufacturers are listed below. If you do not know who made your clock movement, but it says made in Germany, please see the below number examples. If the numbers are similar to what is below, that is who made the clock movement. This is important to know who made the movement, because then we can provide the correct pendulum that will hook up and keep time.
Now that you know who made your clock movement, its time to decide if you would like a metal lyre style pendulum, wood stick or the brass rod style (if you have a wall or mantle unit.)
If the clock kept time in the past and has somehow stopped keeping proper time beyond the adjustments of the pendulum, it is time for a new movement.
If the clock is running fast where before it always kept good time, this means 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 as the entire movement would be disassembled to replace this.
The cost of having someone do this for you 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 and the price would be about the same. Often enough the new movement would be less money than a repair.
So what all this means is to first see if the clock movement is in production and available new instead of having it overhauled. We do this by getting the numbers off of the back plate of the movement itself, right off of the brass, then email this information to us at [email protected] and we will check availability and quote. If the movement is not in production anymore, then a repair is the only option.
Timing issues are always about the clocks pendulum length. It does not matter too much about how much the pendulum bob weighs, or anything else besides the length of the pendulum and what length pendulum the clock is geared to keep time.
So notice on the back plate of the movement what the numbers say, it should say something like 85cm or 94cm if it’s a pendulum run German clock movement. Since most mechanical clocks are German, this is a good thing to explain. The CM length that is stamped on the back plate represents the theoretical pendulum length from the top of the movement all the way down to the bottom of the pendulums rating nut threads.
This measurement includes the pendulum tip to tip, the pendulum leader hanger that it hangs on, and the suspension spring on the very top where the leader hangs from. All three of these components in one measurement should be somewhere around the CM length stamped on the back plate of the movement.
This measurement will vary greatly depending on the weight of the pendulum. So if the pendulum has a very wide pendulum bob, the length of the pendulum will be longer than the CM length on the back plate, opposite for a very small diameter pendulum bob. This measurement may vary a lot. To give an example, a 94cm Hermle movement could have a pendulum length of 32 inches for the pendulum alone, tip to tip, off of the clock, if the bob diameter is 4 inches wide. The same 94cm Hermle movement could have a pendulum length of 38 inches tip to tip off of the clock if the bob is 10 ½ inches wide. You see there is about a 6 inch variance from 4 inch to a 10 ½ inch pendulum bob diameter.
Before ordering a metal lyre pendulum, please understand that the Urgos pendulums have not been made in 20 plus years. What would be happening is you would be getting a Hermle pendulum that will fit your movement.
We will have to cut the hook off of the top of the movement and rivet on a new top hook. This will be noticeable off of the clock but not on the clock. Only the top portion that hooks to your pendulum leader will be different.<>Please understand that we will do our best to guess what length to make this pendulum but there is a chance that the pendulum would need to be shortened or made longer beyond the adjustment of the threads of the rating nut. This means you may have to cut the leader and make it shorter or the top of the pendulum if you need to make the clock pendulum shorter to speed up time and make the timing accurate.
It will be helpful also if you can email a picture of the bottom of the pendulum leader that the pendulum is supposed to hang on. We need to be sure we adapt the correct top hook on the pendulum to hook to this part.
The wood stick pendulums do not always come assembled as many times it may be required on the customer end to shorten the length to their needs.
1. Drill the pilot hole. To assemble this pendulum first you drill a pilot hole in one end of the wood stick and then thread in the threads with the rating nut on it into the hole you drilled. You would take the rating nut off of the threads and then use some pliers to twist the threaded rod into the wood and shorten the length.
2. Insert the bob. The bob is the round disk that goes onto the end of the pendulum stick on the threaded rod that was just installed. The bob has two holes on the back, slide the wood stick in with its threaded rod from the big hole on the top down and through the smaller hole on the bottom. So when this is done you have the stick going into the top of the bob and the threaded rod hanging down below the bob. Now you just put the rating nut back on the threaded rod under the pendulum bob and screw it upward some to about the middle of the threaded portion, and slide the bob down on top of it. This is how the clock is adjusted to keep proper time, if the clock is slow than the rating nut will be turned to raise the pendulum bob some.
3. Mount the top hook. The top hook mounts to the other end of the stick with the hook facing the opposite side of the shiny bob. So the hook will point to the back of the movement in other words. This top hook has tabs you can bend over with the pliers, usually the hook gets placed on the top of the wood stick and both the tabs on each side can be squashed inward as to create a good friction fit so the hook will not slide off.
When you need a pendulum for a clock, the first thing is to look at the back plate of the clock movement for the numbers stamped into it.
There should be, in most cases, an indication of how long the pendulum should be to keep approximate time, if it is a German made movement. Providing it’s of German origin, it will usually have a CM length or a PL length. CM stands for centimeters and PL stands for pendulum length. Usually the Germans 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.
When the movement does not give any indication of the pendulum length on the back plate, it is possible, sometimes, to convert the numbers. Modern (post 1960) Seth Thomas or Mason and Sullivan are examples of two companies who did not include the pendulum length as a stamp on the back plate when using their numbering system. Neither of these companies, in modern times, made any of their movements. Instead, they purchased a large quantity of movements from another company and were allowed to use their own number system on the back plate. This is why there is no indication of the pendulum length. In these instances, we can convert their numbering system to the real manufacturer's numbers which would include the pendulum length.
If the movement has no numbers on the back plate at all, or if there is no known conversion, the best style of pendulum that you can get is a wood stick pendulum. This is the only style of pendulum that can be easily modified. These types of clocks are usually antiques, or of Asian origin, and information such as pendulum length is just simply not available. In this case, the only thing to do is make an educated guess on where the manufacturer intended to have the bob swing back and forth and create a pendulum to that measurement.
To do this, measure from the bottom of where your imaginary pendulum bob would be in the case up to the leader that the pendulum is to hang on. Take this measurement and add approximately an inch or two. This will give you the longest possible length that the pendulum would be in the clock. So now with the longest possible length known, get a wood stick in the length you just measured, as well as a top hook that looks like it will attach, or be modified to attach, to the leader.
Also, from that same link, you can purchase a new bob, if you need one. To get the proper bob size, measure the inside width of your clock case and subtract 4 inches from that measurement. That measurement would be the largest bob size that you could order without worrying about the bob hitting the sides of the case. If you want to go smaller than that measurement, then that is fine too.
Once you receive your new pendulum components, you can now put it together, install it, and see how the clock runs. Remember, the pendulum is going to be at its longest possible length. The longer the pendulum, the slower the time will be. If the clock is running too slow, even after adjusting the bob, you can shorten the stick until the clock is close to keeping the correct time. Start off by shortening the wood stick by an inch and a half, put all of the components back on the pendulum and see how the clock runs with the new adjustment. If it is still too slow, remove the components again and cut off a half of an inch or an inch. This is the procedure to follow until you get the pendulum to the correct length so that the clock keeps the correct time.
This is on the left side on the picture. This is a polished brass style grid metal lyre pendulum for 85cm and shorter movement lengths. The longer lengths usually look like the other picture with the twisted rods.
The brass rod has the top mounting hook and also the threaded bottom with its nut to regulate the timing. The bob with it chosen diameter will go onto the bottom threaded rod and the rating nut under it.
The wood stick will come unstained. This is so the stick can be stained the proper color to match the clock case. The wood stick pendulum consists of the stick with the hardware and also the bob in the diameter chosen. The good thing about wood stick pendulums is they can be shortened if needed.
Custom, please email us the movement numbers [email protected]
Gold tone brass pendulum with leaf decorations on the top of the pendulum bob. Seven inches in length and has a 2 1/2 inch diameter bob that weighs 3.5 ounces. Used with some modern wall and 31 day clocks. This pendulum has a top with a hole in it, so it would hang on a clock with a single hook leader.
R and A style clock pendulum with a hook top and the rating assembly on the bottom to regulate the time. The pendulum is 9 1/2 inches (241mm) long, with a 3 1/2 inch (90mm) wide bob. The R and A stand for Retard or Advance as the time keeping is controlled by the rating nut on the bottom of the bob, lower is slower.
Pendulum with a hole top mount for kitchen or gingerbread style clocks.This is a 7 inch pendulum from tip to tip. This would hook to a modified long suspension C from the pendulum parts page.
We offer the above clock pendulums bobs with various patterns. These are for mantle movements with the F-S regulator that you can adjust the timing. This is because there is no rating assembly to adjust the timing.
This pendulum bob is threaded on the bottom with a rating nut for easy timing of the clock. This can be used on mantle clocks as well as certain wall clocks such as a banjo. Measurement is the diameter of the bob.
This is a 1 5/8 diameter 2.8oz adjustable mantle clock pendulum bob. This is the bob needed if there is no F / S regulator on the front of the clock dial that takes the skinny end of the key. This can be used in place of a F / S regulator as well if finding the right key is not easy. This is on a slider to regulate the time.