Clock Pendulum Leaders
Mechanical pendulum clock leaders for post 1950 movements. These leader will fit clock movements made in Germany after WW2. The first step to replace a lost leader is to visually match one to the old leader. If the leader does not match up to any of the ones listed, please email us. A picture is always helpful. Look to see if the leader needs a double hook or a hole top in order for it to mount to the suspension spring. Similarly, check the other end and notice that configuration as well. What is the required mount style for the pendulum to hang on the clock? In the middle section, what one will engage with the swinging crutch on the back of the movement? These are all important factors to consider when replacing the leader.
The length of the leader
If the leader is missing, however, there are some more steps to figure out what the leader length should be. Not all leaders have variable lengths and the ones that do are for Hermle and Kieninger clock movements only. Kieninger is easy. Those leaders only come in two lengths. Grandfather clocks by Kieninger take the 7 inch leader. Wall and mantle units take the shorter leader. Hermle leaders are much more involved. Determining which leader is the correct length for a Hermle is a process. The next section will describe the ones available.
Hermle leader lengths
A Hermle floor or wall clock will always take leader D or G. leader E is for a low bridge to a high bridge conversion on a Hermle grandmother clock. Therefore, this can be eliminated from the choices if a conversion is not being done. The next choice is leader F which is for mantle clocks. This one is also used to create custom pendulum lengths. Additionally, leader F and leader G are interchangeable. So if a custom leader G is needed, a leader F can be used in its place with an alternate length. Please email us with any questions about Hermle leaders.
Leader F for Hermle mantle
Usually mantle clocks with a Hermle clock movement will take leader F. In a situation where the leader is missing and the length is unknown, the following steps need to be taken. This will ensure that the correct leader length is chosen. First, use the CM number off of the back of the movement. This CM length is the pendulum length from the top of the movement all the way down to the bottom of the pendulum. It is not the length of the pendulum itself. Often times this measurement can be confusing. It is important to measure this correctly. Failure to do so will result in the clock not keeping proper time.
Second step, is to take this CM length and divide it by 2.54 to get the inch equivalent. Then subtract the length of the pendulum and the suspension spring length from this measurement. The measurement that is left is the length needed for leader F. There are 1 1/2 inches of thread at the bottom of the pendulum for fine adjustment. Because there is so much room for adjustment, this measurement does not have to be exact. If there wasn't any extra length then it would need to be more precise. However this is not the case so close is good enough.
If the leader is the wrong length
The timing of a clock is determined by the length of the pendulum and the weight of the pendulum bob. This can get a bit confusing for some people. The overall pendulum length is stamped on the back plate of the clock movement with a CM number. This CM stamp is the overall pendulum length from the top of the clock movement all the way down to the bottom of the rating nut. This is based on the smallest bob diameter. Subsequently, a wider pendulum bob will require a longer pendulum. Again, this can get a bit tricky. Please feel free to send an email with any questions. We will be glad to help.
Often enough a clock will either run too fast or too slow. If the pendulum is too long, the clock will run slow. On the other hand, if the pendulum is too short the clock will run too fast. In addition, the wrong leader length will also create problems with accuracy. This may or may not be corrected by raising the bob up or down. This is done by turning the rating nut below the bob. If all else fails, a different leader length may need to be purchased. Before shortening a pendulum it would be best to contact us to see if this is the best option. Cutting the pendulum is the last resort.
As seen, this is not a cut and dry procedure. There are many factors that play into getting the correct combination so the clock will keep correct time. The correct leader is just one part of the whole process. Sometimes all it takes is a leader that is a bit longer or shorter to correct an issue. There are also times where we have custom made leaders for customers. Measuring is also important. No matter what situation it is we can surely find a solution. Don't ever hesitate to reach out and ask a question. Pictures are always good to send so we can see what exists now. Email is always the fastest way to contact us.
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