Both lever escapement and coaxial escapement are types of mechanical watch escapements used to regulate the movement of the watch’s gears and hands. However, they differ in their design and functioning.
The lever escapement is the most widely used escapement in mechanical watches. It consists of an escape wheel with pointed teeth that interact with a pallet fork, which rocks back and forth as the balance wheel oscillates. The pallet fork is connected to an anchor, which has a locking face that interacts with the escape wheel teeth. The escape wheel rotates, and the teeth push the pallet fork, causing it to momentarily lock and then release, allowing the balance wheel to oscillate. The lever escapement is reliable, robust, and relatively easy to manufacture, making it a popular choice for many watchmakers.
The coaxial escapement, on the other hand, was developed by George Daniels in the 1970s as an alternative to the lever escapement. It uses a different mechanism to regulate the movement of the watch’s gears and hands. The coaxial escapement has a smaller number of parts than the lever escapement, which means it requires less lubrication and is less prone to wear and tear.
In the coaxial escapement, the escape wheel interacts with a set of three pallets, rather than the two in a traditional lever escapement. The pallets are arranged in a way that allows them to slide, rather than rock back and forth like in the lever escapement (Ed: that seems to be incorrect, according to Wikipedia: “…the coaxial escapement functions with a system of three pallets that separate the locking function from the impulse, avoiding the sliding friction of the lever escapement.”). This design results in less friction and better accuracy. The coaxial escapement also has a unique design that allows the balance wheel to oscillate in both directions, further improving its accuracy.
In summary, while the lever escapement is a traditional and reliable choice, the coaxial escapement is a modern alternative that offers improved accuracy and requires less maintenance.
(Image: Dall-E: “a photograph of a coaxial wrist watch escapement”)