Da Vinci is very serious when he works. As one of the most outstanding mechanical engineers of the contemporary era, Da Vinci is also very proficient in mechanical manufacturing. Although Da Vinci was not very proficient in making clockwork, it didn't mean he couldn't.
Under Marlin's strong onlookers, Da Vinci showed how to build gears and clockwork...
But what surprised Marin was that Da Vinci made gears and springs, not only completely by hand (nonsense, where is there a machine tool for him?), but also without any high-precision measuring instruments.
For example, when making gears, Da Vinci first calculated the size, then roughly measured the mold and cast the billet. Then, take the blank and start sanding by hand. After a while, take out a "standard" reference object for physical comparison. After the comparison, if there is no problem, put it into use directly. If there is a problem, continue to grind... If the grinding is too much, it is smaller than the standard reference size, and it is directly scrapped...
Marin looked a little dumbfounded:
"Ada, didn't you calculate the size in advance? Why do you need to grind it?"
"What's the use of calculating it? The error is still too big..."
Then, through Da Vinci's explanation, Marin knew that in this era, the smallest unit of length in Europe turned out to be an inch...
Moreover, there is no vernier caliper in the modern sense in Europe at present, and only the UK has a ruler similar to a vernier caliper - a caliper. Of course, because this caliper does not have a precise scale, the measurement is not very reliable.
It stands to reason that the manufacture of gears and springs should be regarded as very precise devices, requiring very precise specifications and scales. However, in this era, when people manufacture precision components, the units that can be accurate are only estimated to be about one-tenth of an inch, which is less than 1 millimeter. Therefore, when Marin watched Da Vinci make gears and springs, he often saw Da Vinci rework and grind again. Because, although the previous calculation is not bad, due to the large measurement error, there are often cases where the parts do not match, and it needs to be re-polished. And once worn too far, the parts have to be scrapped.
In this era, the difference between a master craftsman and an apprentice, apart from knowledge, lies in the grinding skills. For example, great craftsmen have good craftsmanship in grinding parts, and when they are close to the scale, they will be very careful, so that few parts are worn out and the yield is high. As for those apprentices, often at a critical moment, one of the controls is not good, and the parts are scrapped. Even if it is not scrapped, the running-in between parts is not very good because of poor manual control.
Moreover, it is also very difficult to check the quality of workpieces in this era. It is necessary to take out "standard" workpieces and compare them carefully against the sun, which is a test of eyesight.
Unlike later generations, the parts are all fixed in size, and the quality inspectors can see how big the error is as long as they measure with a vernier caliper. Then compare the table to see if it is within the allowable error range, you can judge whether the workpiece is qualified...
"It would be great if there was a vernier caliper!" Marin said with emotion.
However, before making vernier calipers, Marin had to get the weights and measures right first.
Because, in this era, there is no measurement of centimeters and millimeters, and Marin needs to define it himself. Moreover, the vernier caliper is very precise, and the lowest scale of an ordinary vernier caliper has also reached the 0.1 mm level. Basically, a 0.1mm vernier caliper is absolutely sufficient in this era. Even, up to the industrial level of the 19th century, this scale is quite sufficient.
But, because there are no scales for meters, decimeters, centimeters and millimeters yet. Therefore, first of all, Marin needs to "create" such weights and measures by himself.
But for European weights and measures, Marin is most familiar with imperial units. For example, the length, one inch = 2.54 centimeters. And the weight, one imperial pound = 453.59 grams...
So, to figure out how long a standard centimeter is, you just need to figure out how long it is in a standard inch. Then, according to the principle of 1 inch = 2.54 centimeters, the length of 1 centimeter can be quickly calculated. Then, every tenth of a centimeter is 1 millimeter...
Meanwhile, 1 standard British pound is equal to 453.59 grams. Therefore, as long as you get the standard weight of 1 British pound (copper weights are generally cast in various countries as a standard weight reference), you can deduce that 1 gram is a variety of…
For this reason, Marin arranged for people to go to the UK, tried every means to contact the British court, obtained standard feet, inches and British pounds data, and brought them back to Den Burg.
Then, under Da Vinci's amazed gaze, Marin deduced the lengths of 1 centimeter, 1 decimeter, 1 meter and 1 millimeter. Then, with the British pound, weights in grams and kilograms were deduced.
After that, Marin arranged for craftsmen to make standard reference copper rulers of 1 meter and 1 decimeter out of copper, and made standard copper weights of 50 grams, 500 grams and 1000 grams out of copper as standard reference weights. . After making reference materials, these standard items were sealed up and wrapped in paper. Take it out for comparison and use only when needed.
After the weights and measures were set, Marin asked Da Vinci to help build a vernier caliper. Then, Leonardo da Vinci, who was well-crafted, made a very standard copper vernier caliper under the theoretical command of Marin, and the scale used was also accurate to 1 mm. Although it didn't reach 0.1 mm, it was enough. Because, in the era of hand-made devices, 1 mm is considered a very precise scale. As for the error, experienced craftsmen can actually feel it.
With vernier calipers, it was much easier for Leonardo da Vinci to make gears and springs. For example, when casting gears in foundry, you don’t need to take out standard reference objects, but you can directly make molds according to standard sizes, and then start casting...
Marin also told Da Vinci that the vernier caliper can actually be accurate to 0.1 mm, but due to the level of manufacturing technology, it is difficult to manufacture a vernier caliper with an accuracy of 0.1 mm. Of course, with Da Vinci's craftsmanship, if you spend more time and scrap a few more, you can also manufacture a vernier caliper accurate to 0.1 mm.
Hearing what Marin said, Da Vinci was also interested. So, he suspended other affairs and concentrated on making vernier calipers. Finally, after scrapping dozens of them, three relatively standard copper vernier calipers were made.
With such a high-precision vernier caliper, Da Vinci himself felt that it was much easier to manufacture gears and clockwork steel wheels. In the past, Da Vinci had to take out the real objects for repeated comparisons to see whether the quality of the gears and springs was qualified. But now, if you want to know whether the size is standard, you just need to take out the vernier caliper card and measure it, and it will be done easily. In this way, Leonardo Da Vinci, who was not good at making clockwork, also made a clockwork with a very standard shape.
Of course, it's just the appearance standard. Regarding the quality, Da Vinci said frankly that the standard clockwork steel wheels are made of refined steel repeatedly forged by excellent blacksmiths. The steel wheel made by Da Vinci is simply made of wrought iron provided by Marin. Although the size is very standard, the internal stress is wrong and needs to be adjusted.
However, for Marin, a traveler, he knows that it is best to use spring steel with the best elasticity for the clockwork steel wheel. The simplest spring steel is actually a kind of tool steel (high carbon steel). And the steel bars that are repeatedly forged are actually the blacksmiths repeatedly heating and forging, which reduces the carbon content of the pig iron and turns it into high-carbon steel.
Therefore, for the steel bars that people in the Middle Ages seemed to be difficult to process, Marin knew that it was actually easy to manufacture, as long as the carbon content of the steel was kept at 0.62~0.90% (belonging to the lowest grade of carbon content in high-carbon steel, close to medium carbon steel level), add some manganese (the content is about 1%, specifically 0.90~1.20%, but in actual control, it is not so precise, as long as it is almost usable), and then after simple heat treatment, the lowest Grade spring steel—65Mn steel.
With 65Mn steel, the quality should not be much better than the steel bars that the current blacksmiths have repeatedly forged with pig iron bars. Moreover, because there is no need to spend so much labor to repeatedly forge and process, the cost and working hours can be greatly reduced.
In fact, many steel knives in ancient China used this similar "thousands of tempering" method to repeatedly heat and forge a piece of pig iron to reduce and consume the carbon content inside it, and finally obtained steel, also known as "Hundred Refining". steel". The so-called refined iron is actually obtained in this way.
However, through scientific methods, Marin can directly smelt pig iron or wrought iron into steel, which saves the need for repeated forging. It not only saves man-hours, but also greatly reduces costs. Moreover, the quality of the two is similar.
Of course, to produce qualified 65Mn steel, Marin also needs some time and the help of some craftsmen. However, since Marin, the traverser, has the technical guidance, it is only a matter of time before the 65Mn steel is produced.
And once the 65Mn steel is produced, the production of clockwork does not require blacksmiths to heat and forge repeatedly, and spend a lot of energy and fuel to process pig iron bars into steel bars. At that time, the production costs of clockwork steel wheels, chains and springs can be greatly reduced.
And if the production cost of these parts is reduced, then the production cost of the originally expensive revolver can be reduced a lot. Like this, also greatly facilitate the mass production and the installation of the rotary flint gun.
…
Because of the improvement of weights and measures and the appearance of vernier calipers, Leonardo da Vinci found that it was much easier to process clockwork steel wheels, chains, and springs. As long as you remember the size and position of the part with the best properties, and put the vernier caliper on it, you can accurately judge whether the part is qualified or not. Then, according to the standard requirements, let the craftsmen make slight adjustments and processing. In this way, the production of precision parts is much more convenient...
The only trouble is that Da Vinci seems to be a little uncomfortable with the new weights and measures. Even if the value is measured, I always unconsciously convert it to the old size in my heart. However, Marin believes that the standard decimal system of weights and measures popular in later generations is much more convenient than the old weights and measures, whether it is calculation or memory. As long as you use it for a long time, you will find it more convenient and practical than the old-fashioned weights and measures...