The Origination of the Foundation of a Timepiece - The Mainplate

Jean-Antoine Lépine (1720-1814) Father of the Modern Mechanical Watch

I have been blogging about watches for years and I have read thousands of other articles and posts.  I have blogged about, the mainspring, escapement, balance wheel, gear train, crystal, watch case, strap, buckle, indicators, hands, crown, lugs e.t.c, but I rarely concentrated on the basic structure and foundation of the watch: The Main plate. Of course watchmakers pay close attention to this component,  as the perfection of the main plate is the first step in creating the perfect watch and often its design is the most discerning company trademark.

Even though, some watch companies like Swatch has sought to do away with a mainplate by affixing everything onto the case, and some have used a chassis like structure for watch components, the main plate is still the basis for most watches, mechanical and quartz.

What is the Mainplate of A Watch? 
The Mainplate is the base or foundation of a movement to which various watch components are affixed.  Most often the mainplate is made from brass (an alloy of copper and zinc)  - a stable,  antimagnetic material that is malleable and can be worked cold. The mainplate begins as a smooth round disc, after which it is machined to accommodate components of the movement as well as the various movement bridges.Often the mainplate and bridges are signature to the manufacturer and with the keen eye of a watch expert, one can determine the origin of the manufacturer without additional clarification.   Precise crafting of the mainplate is essential to watch accuracy like the foundation of the house, whose very structure is based on the soundness of the foundation.  An imperfection of the mainplate results in an integral inaccuracy of all the other mechanisms of the watch no matter how perfect they are.   The main plate is often overlooked and underestimated since it is rather an inconspicuous part of the watch. 

The Evolution of The Mainplate

Granted the mainspring is the oldest component of  a watch dating back to the 1600's, since it was the first successful way to conserve and emit energy and yet the mainspring needs to be mounted onto the main plate. Directly prior to the evolution of the mainplate,  timekeeping was kept by means of pendulum clocks.

 The main plate seems to have almost erupted as being just obviously there with no more discussion on the matter.  I did ask a member of the esteemed Horological Society of New York- founded in 1866 -  and he suggested the circular main plate evolved out of necessity around the transition time from clocks to watches and from verge and foliot to stack-freed to fusee.  The 16th Century pocket watch incorporated with the stack-freed  utilized the empty space on the outside of the back plate in the pocket watch.   Thus still no indication of a mainplate.  However the more efficient fusee, used from the 15th century up until the 20th century,  does require  two plates to affix the mechanism.

A major break through in history of the main plate occurred in 1770. One of the greatest watchmakers of all times and Clockmaker to the King, French Jean-Antoine Lépine, designed a movement with a single plate. This construction was the first timepiece to transition from the hefty two plate movement, some of which reached great thicknesses of up to 38mm (now we are used to that kind of measurements in watch diameters not height or thickness)  to that of a single plate. He did away with the cumbersome fusee, a mainstay in timepieces since the mid 1500's, and  utilized the going barrel. In addition he individually pivoted the majority of the wheels in the train.    The revolutionary new Lépine calibre became the basis for all mechanical watch movements as we know them today. Thus we can say that Jean-Antoine Lépine is the father of the modern mechanical watch and  Breguet ,of course, fine tuned the mechanism. Countless movements have evolved from the Lépine calibre to such an extent that the origination of the main plate has dimmed through the passage of time.

I would love feedback on this discussion.


Reference: 

The National Association of Watch & Clock Collectors - www.nawcc.org