Cylinder escapement is a resting escapement that was mainly produced in the 18th and 19th centuries.

It was invented in 1965 by Thomas Tompion.

Unlike the Swiss lever escapement, the most common escapement today, the cylinder escapement has fewer components. While the Swiss lever escapement has three main components, escape-wheel, pallets and balance wheel, cylinder escapement has only two main components, balance wheel and cylinder wheel. Therefore, there is no pallets on the cylinder escapement. It is the cylinder wheel that does the function of the escape-wheel and the pallets.

This escapement often has a pin on the outside part of the balance wheel a part called felloe, which is designed to prevent the knock that could create more trouble on this escapement than on others. The axle of this balance is made of a cylinder that has an opening with very precise angles that will be in constant contact with a tooth of the cylinder wheel, that’s why it is called a constant rest escapement. This balance shaft is made of three parts, the cylinder and two pads on each side which are the pivots of the balance shaft. A very important part of this escapement is the cylinder wheel. Many master watchmakers warn their apprentices when working on this kind of piece not to break the cylinder wheel because this would mean the end of the piece, the production of a new wheel would be unrealistic in view of the market value of this type of watch.

This escapement is therefore a resting escapement which must reverse a little the logic of a modern watchmaker who often replaces an old barrel spring by a new one during a revision. Indeed the old blue steel springs are often replaced by white metal springs more modern and also stronger. They can be thinner and longer and thus have a greater power reserve. But on a cylinder escapement, which is at rest, putting a stronger spring could only increase the friction and lower the amplitude of the watch. This is the reason why a well trained watchmaker often leaves the original barrel springs in these cylinder escapement watches.

These pocket watches with cylinder escapement are often interesting pieces at affordable prices. An ideal historical watch to start a collection.