Double End Clock Key (F / S at 12) Note
Some clocks have a small place that looks like a mini clock winding arbor at the 12. It may say F / S or A / R. The F / S this means fast or slow, and the A / R represents advance or retard. This controls the timing of the clock and turning it to fast or advance makes time faster opposite for slow. An ideal double end key fits both the winding arbor to wind the clock and also fits the smaller time regulator aspect. This is not easy to get and at the same time is the most lost part. It is possible to regulate the clock another way with an adjustable bob instead of a fixed length bob.
Get the double end key the hard way
Using the clock key size chart you can get the right size that the clock requires. This chart works for both the fast / slow regulator and also to wind the clock. However, this is not easy because it requires a measurement of the post the double end key fits onto. In order to get this measurement remove the clock movement or the dial. Without access to the front of the movement it is hard to measure exactly how wide the arbors are that the key is to go on.
Double end clock key the easy way
There are many sizes and combinations for the double end key and it may be tricky to get the right size. So you may just want to get the 4 pack of double end keys we offer. This is the top 4 most common double end clock keys that are used so the odds are one will be the correct key. Ideally this will supply the clock with a key that fits both the F/S regulator and the winders. However be aware this 4 pack does not guarantee one will work.
An alternate method
It is possible to forget the whole double end key game and use a single end key instead. It does make things easier and is a better long term solution. Inevitably, once you get the perfect fit the key will get lost again. This seems to be the trend of what happens. Once the key is separate from the clock, there is a higher chance of it getting lost. Many times we suggest putting the key in the bottom of the clock case for safe keeping
Using an adjustable bob instead
The solution to the double end key problems is to get the single end key to wind the clock. Also get the adjustable bob. The adjustable bob can be regulate the clock with the pendulum instead. The bob will have a nut on the bottom. Raise the bob on the pendulum to speed up time. The opposite is true for slowing time down. Once you regulate the clock, it will stay this way for the most part. Some timing may or may not need to be done when the temperature changes vastly. For the most part, time the clock and it will stay that way within a couple of minutes a day all year long. The adjustable pendulum bob comes in three sizes, or bob diameters. The middle or smaller diameter bob is fine for most clocks because the weight is not as important as the length.
Parts available to purchase
Other parts to consider besides the double end clock keys. We have two styles of the adjustable pendulum bobs. One of them is the three sizes of bobs that have the nut underneath. We call this the Adjustable Mantle Clock Bob. There is another style bob that is adjustable from the back side. We just call it the Adjustable Antique Style Mantle Clock Bob. They both function the same, it has a bob on the pendulum that can regulate the time. The part they hang onto is usually a long wire with flex spring steel on the top. This gets bent and cut into shape for the desired length. It comes in a three pack and we call them the Long Suspension Spring Rods.
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