In this instructable I'm going to show you how to print your own pocket watch! The thought of trying to make one is probably quite daunting, and in fact, it is quite the challenge, but lucky for you, I've already suffered through it so you won't have to!
Basic Pocket Watch Movement from Matthew "Rick" Shaw on Vimeo.
We'll need to look at how a mechanical pocket watch works so we know what we're getting ourselves in for. There are a few good videos online, this one is short and explains it very well, though it is just a demonstration and doesn't quite explain everything, while this one is considerably longer, but is still completely accurate and extremely useful for figuring out what we need to make. In case you don't want to watch them, or don't have the time, I'll give a quick explanation here:
The Balance Wheel is the key to the watch. It is attached to a spring, and is pushed by the Fork Pin. When pushed, it spins a little before the spring pulls it back, knocking the fork pin on it's way past, which gives it an extra little push to continue the momentum. By doing this, the fork pin is able to quickly move from side to side, allowing two paddles to catch and release a wheel with long pointed teeth called the escape wheel. This is the ticking sound you hear from watches, and is what controls the speed of the watch. A series of gears are attached which pass the motion on in a way that gives the correct rate for each hand. The power for the watch comes from a second spring inside the barrel of another gear. When you wind the top, the spring is tighetened, and releases slowly, pushing the chain of gears.
So, now that we have an idea of how the watch works, we can begin to look at how we're going to make it and some important facts to keep in mind.
Note: It is of course, impossible to entirely print a watch as there are two springs required which cannot be 3d printed as then they would not have tension. The spring for the balance wheel must be careful made to ensure the correct motion of the balance wheel. Similarly, if you want a glass front, you'll obviously need to get the separately, although with the rise in 3d printing, many companies are offering a clear material.