Nowadays, large quantities of parts mostly resort to automated machines. In this article, we will introduce how to make movement gears manually. The following is a diagram of the finished gear: the total length is 3.19 mm, the diameter of the addendum circle is 1.044 mm, and a total of 8 teeth. Now, let us take a detailed look at all the steps to make this gear.
Material: Sandvik 20AP high-carbon free-cutting steel round bar with a diameter of 2.5 mm. High wear resistance, high machining accuracy, small heat treatment deformation, superior mechanical properties, widely used in the production of precision clock parts. Adjust the cutting of the blank to the proper diameter, the largest part should just be fixed on the fixture of the gear processing machine tool, and the two ends of the fake watches blank should be of moderate length and spare. Take a dial indicator to check whether the blank is properly placed, rotate the blank, and the value on the dial indicator should not be changed.
Adjust the gear milling cutter lever to cut the length of the teeth, and the index wheel at the back is used to fix the number of teeth. The cutting process itself is very fast, and the preliminary preparation of the machine setting is more time-consuming. A movement contains multiple gears of different sizes, and each size of gear requires different gear milling cutters.
When the gear milling cutter of the required size cannot be used or is not nearby, a skilled watchmaker can make the milling cutter by himself. The picture below is a hand-made custom gear milling cutter. The production of this gear milling cutter is complicated and tricky, and the setting and adjustment of the blade cutting angle is very subtle.
Why add coal powder? Under hardening temperature conditions, steel will react with oxygen in the air and start burning. Pulverized coal has a lower ignition point than steel and can consume oxygen to prevent steel from burning, keeping it clean and intact. The industrial hardening operation is based on the same theory, but realized under nitrogen instead of air. Then there is annealing, the purpose is to reduce the hardness of the steel and improve its machinability. Slowly heated to a certain temperature, the gear will gradually show different colors, light straw, indigo, dark blue and light cyan replica watches, each color corresponds to a specific temperature and annealing degree. Our goal is to anneal the pinion to dark blue in order to obtain the best hardness (this is also the process of making blue steel screws and blue steel hands). The bluish pan is covered with brass shavings that are evenly heated.