Although screws are inconspicuous in mechanical watch components and can be seen everywhere, they are one of the indispensable main parts. For precision mechanical timing tools like mechanical watches, screws are more important, so how many screws are there in the movement of a mechanical watch, and what are the functions of these screws? Today we will show you what kind of big role this small screw plays!
Everyone knows a watch, from the buckle, bracelet, lugs, case, to the movement, there are more than a dozen different types of screws that can be seen by the naked eye. If the mechanical watch movement is further disassembled, more types and quantities of screws can be seen. Take a watch with the simplest function as an example, its movement contains at least 20 screws, and it is not surprising that a watch with a complex mechanism has 30-40 screws, and there may be more.
In fact, these screws are the same as ordinary mechanical purposes. They are used to connect or fix movement parts (or mechanisms), so that everything in the watch can operate freely. So each screw has its own use.
Although there are many kinds of screws for custom mechanical watches, they all have parts such as screws, nuts, and threads in common. In fact, in the earliest days, many screws of watches or pocket watches were made in imperial system, and some of them also used metric system, which was confusing. The main performance is that the screws are generally long (but not uniform), the diameter of the screw head is small, the height of the screw head is also thick, and the styles are different.
1. Cylindrical head screws are used for splints, compression springs and other parts;
2. Small cylindrical head screws are used for the dial foot and the outer pile of the hairspring;
3. Semi-sunk head screws are used for the small steel wheel, fork splint and other parts;
4. Countersunk screws are used for compression springs, cross-wheel pressing pieces, lower brackets, etc.;
5. For splint screws, the top polished ones are spherical cylindrical head screws;
6. The function is the same as that of the large cylindrical head screw, because the top area is larger, and the top must be polished, so the large cylindrical head screw;
7. Large cylindrical head screws used in multiple parts such as pawls, compression springs, large and small steel wheels, splints, and fixed movements;
8. The one-level platform used for ratchets and levers does not have a fastening effect, and the mechanical watch components that can move around the second-level platform are screws with steps;
9. Non-standard screws, used for special parts, are pull-out screws. It should also be noted that the screws in the movement can be divided into positive buckle and reverse buckle.
In addition to distinguishing the screws by their working parts, there is also a distinction by color. For example, our common "baked blue" steel screws are generally visible to the naked eye on the surface of the plywood. The movement of some models of custom mechanical watches is just to make the screws on the automatic splint dark blue.
In addition, it can be distinguished from the appearance characteristics of the screws. Generally, the screw heads are not polished or just matte. Such screws are often used in low-end watch movements, and the movements in some high-end custom mechanical watches are more secretive. (on the cover spring, calendar parts and fixed disc feet), or on miscellaneous items on the dial surface.
For high-end first-line brand watches, screw production is quite exquisite, which is an important part of movement polishing. The surface requires fine grinding and polishing, with chamfers and slightly curved surfaces, which are very appreciative.
The last thing to watch out for are those screws with "triple grooves" in the cap (turned-back screws), which rotate in the opposite direction than normal when installed. If you turn it in the wrong direction, it is easy to break the screw and get stuck in the hole. Generally only used for small steel wheels.