Have you ever wondered how a watch keeps time? It’s all thanks to the motion works, which is made up of several components that work together to make sure that the hands turn accurately. In this blog post, we’ll be exploring how these components fit into the puzzle and what tools are needed for servicing the Motion Works. We’ll also discuss the importance of understanding how they all work together in order to properly assemble and service watches. So if you’re interested in learning more about the fascinating part of the movement

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Overview of the Motion Works

The motion works in the St36 is an assembly of several wheels and gears that serve 2 purposes. It is used to transfer the stem’s motion through the keyless works to manually change the time. Its second job is to transfer the motion from the center wheel to accurately display the time through the hands that are attached to the canon pinion and hour wheel.

When the stem is pulled out to its second position, the groove of the stem holding the pin of the setting lever forces it forward so that its teeth mesh with those of the intermediate wheels. The intermediate wheels eventually connect to the hour and minute wheels. Thus, it sets and keeps time as desired.

Parts of the Motion Works

The motion works consists of several key components that must be in good working order for the movement to run smoothly:

Canon Pinion

This component connects the Center Wheel to the Minute Wheel. The Center Wheel makes one revolution every hour and that is the reason the Minute Hand is attached to it. In this case, the Canon Pinion is friction fit to the extended arbor of the Center Wheel. As the Center Wheel Turns, the Canon Pinion turns. it is friction fit tight enough to turn with the Center Wheel, but it also needs to be loose enough so that it can be turned by the gears when setting the time so as to not disrupt the running of the watch. The bottom of the Canon Pinion has a pinion that engages with the teeth of the Minute Wheel.

Canon Pinion on a ST36
Canon Pinion on an ST36

Minute wheel

The Minute Wheels’ job is to reduce the speed that the Canon Pinion turns by stepping down the gearing ratio to the Hour Wheel so that it only rotates twice per day. It does this by the number of teeth that mesh with the Canon Pinion, which is further reduced to its own pinion which meshes with the teeth of the Hour Wheel.

Minute Wheel on St36
Minute Wheel on an St36

Hour wheel

The Hour Wheel Fits over the Canon Pinion and is where the Hour Hand is attached. Because the gearing ratio of the Motion Works is a reduction, this enables the hour wheel to make one complete rotation every twelve hours.

Hour Wheel on a ST36
Hour Wheel on an ST36

Intermediate Wheels

These are two smaller-sized gears that receive power from the sliding pinion. These gears transfer the motion from the Sliding Pinion of the Keyless Works and turn the teeth of the minute wheel. This motion connects them to the hour and minute wheel, allowing them to set the time.

Intermediate Wheels on a ST36
Intermediate Wheels on a ST36

Assembling the Motion Works

When assembling the Motion Works, you want to install the Canon Pinion first when it is friction fit. If the minute wheel is installed first, you run the risk of damaging its teeth when the Canon Pinion is snapped into place.

Installing Canon Pinion on St36
Installing Canon Pinion on an St36

Once the Canon Pinion is in place, then you can install the minute wheel, the intermediate wheels, and then the hour wheel.

Installing the Motion Works an a St36
Installing the Motion Works an St36

Lastly, many watches will have a dial washer that sits loosely over the Hour Wheel. It has a slight curve in it and its purpose is to add a little friction between the back of the dial and the hour wheel to keep the Hour Wheel seated in its place.

Dial Washer for St36
Dial Washer for St36

Types of Tools for Removing Cannon Pinions

Now, let’s discuss the tools you’ll need to remove cannon pinions. There are two types of tools available for this task: the Bergeron 4854 and the Canon Pinion Presto Tool.

The Bergeron 4854 is a more expensive tool that can range anywhere from $150 to $250. This is great for any watchmaker who needs heavy-duty power when removing cannon pinions.

Bergeon 4854
Bergeon 4854

On the other hand, there’s the Cannon Pinion Presto Tool which retails for a fraction of the cost and is great for anyone starting out in watch servicing. The amount of resistance that a cannon pinion has when you’re removing it is usually very small, so this tool should be more than enough.

Canon Pinion Presto Tool

So if you’re just starting out in the watchmaking world, my recommendation would be to go with the Cannon Pinion Presto Tool. It’ll save you some money and will give you all of the power that you need for removing cannon pinions.


In conclusion, there are several components that make up the motion works of a watch, and understanding how they all work together is very important. The Canon Pinion is an essential part of the system as it connects the Center Wheel to the Minute Wheel which connects to the hour wheel and reduces the Center Wheels speed so that the Hour Wheel only rotates twice per day. Additionally, when removing the Canon Pinion, a watchmaker should use either the Bergeron 4854 or the Cannon Pinion Presto Tool to ensure that they don’t damage any of the gears. By understanding how all of these components work together, a watchmaker will be able to properly assemble and service their watches. Thank you for reading!