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Mainspring and barrel

Mainspring and barrel


    The mainspring provides the power for the movement,  it is one of the most important and and frequently overlooked parts of a mechanical timepiece.  The mainspring is contained in the barrel and wound by the arbor.  The barrel components consist of the barrel and the barrel cover which have bushings in them through which the arbor is held in place.  The barrel arbor has a small hook on it which catches the hole in the end of the mainspring and the arbor also has shoulders on which the barrel is carried and pivots on it’s ends that hold the barrel complete in place between the barrel bridge and pillar plate.  The arbor also has a square on it’s top end and is drilled and tapped, this square accepts the square in the ratchet wheel and a screw holds the ratchet wheel in place on the arbor.


    The barrel complete is held between the pillar plate and barrel Bridge.  The barrel bridge is held in place to the pillar plate by screws and steady pins.


    To remove the barrel, first remove the ratchet wheel, now remove the bridge screws, then the bridge can be popped up using edge of screwdriver.  Most movements have notches cut into the edges of the plates and bridges to accept the blade of a screwdriver to release the bridge from its mating surface.  After the barrel bridge has been removed the barrel can be

    To remove the mainspring from the barrel you will have to pop of the cover.  To remove the cover place the blade of a small screwdriver into the cutout in the edge of the cover and pry the cover up carefully until it pops off.  Some barrel covers do not have a notch and need to be popped off by pushing on the arbor from the opposite side.


    After the cover has been removed use a pin-vise to grip the top pivot of the arbor and remove the arbor with a twisting motion.  The mainspring can then be removed by pulling up on the center coil with a sturdy pair of tweezers until the coil clears the top of the others, then carefully allow the mainspring to slowly unwind out of the barrel using your fingers, taking care not to allow the spring to suddenly pop out all at once.

Some common mainspring end types pictured bellow


Mainspring shapes pictured bellow




About the Author:

About Carignan Watch Repair Company Carignan Watch Company was officially started in January 1996. However, long before that, owner Denis Carignan was repairing watches as a hobby. It all began when he found an old pocket watch while antiquing. He was amazed by the craftsmanship and became captivated by what is known as horology. Over the years, we have repaired and restored thousands of timepieces. We specialize in repairing the timepieces that others give up on. Carignan Watch Company has a large inventory of parts and materials, and we also manufacture parts that cannot be purchased due to age or rarity. We service a variety of timepieces. We are an independent repair shop; we are in no way authorized by, affiliated with, or endorsed by ANY watch manufacturer, company or re-seller, and we like it that way. About Denis Carignan, Owner, Carignan Watch Company Many years ago I fell in love with watches and, like many others, I tried having a few serviced by so-called watchmakers and was very disappointed . The “factory authorized service centers” were even worse to deal with unfortunately. When I say I fell in love with watches, I mean it. They fascinate me on many levels and I think it is an absolute shame that it is difficult to get them serviced properly. I began repairing my own watches and before long I jumped in with both feet. From that point on, watches and the repair of them has been my passion, or perhaps obsession. I have devoted nearly all of my adult life to learning the craft and have been providing people and their watches the best possible services available for may years. When someone says “it cannot be done” or “you can’t fix this,” it sparks something in my mind that is hard for me to stop. At times I have spent hundreds of hours on a project that many other watchmakers had abandoned, determined to see it through no matter what. This is usually not profitable, but it sure is nice to see the look on the customer’s face when I hand them their running watch that is for all intensive purposes “back from the dead.” If I don’t know something, I ask someone. If I do not have something I need, I find it. If I cannot find something I need, I make it. If something is truly beyond my ability, I admit it and try to find someone who can help. If help cannot be found, I will do everything possible to learn how to do it myself. I take pride in my work, which I enjoy, and I am grateful to God for the abilities he has given me and plan to use those gifts for as long as I can. I came from a long line of engineers, machinists, and inventors, on both sides of my family, so it’s no wonder, I guess, that I am so interested in mechanical things. Every thing I have I worked very hard for. I hope someday my daughter will get into the business, but only time will tell; she is still young. I am self-employed and independent from any watch manufacturer at this time, for a reason. I do not like being dictated to and refuse to do things that I do not agree with. I am always working on honing the skills I have and learning new ones. I am very well connected and do not shy away from the tough jobs. I take the training I want to take. I work on whatever watch I want to work on, and I use the tools and equipment that I want and deem appropriate to use. I use both antique tools and modern tools that I have purchased over the course of many years. My shop is extremely well equipped and exactly the way I need it and want it. Very few shops have the capabilities that mine does. In my opinion, you should be able to bring your watch to whomever you want to have it repaired; it is your watch and your money. The person you bring it to should be able to get the training, parts, and equipment to service your watch easily and cost effectively, without jumping through constantly-changing hoops and hemorrhaging money. Pomp and circumstance is not something you will find here.
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