The waterwheel drives the gears, and the big gear drives the small gear, and after such multiple transmissions, the belt made of raw cowhide drives the belt shaft to rotate extremely fast, and with the rotation of the belt shaft, on a wooden simple lathe, a pine wood nearly seven feet long is quickly rounded under the cutting of the cutting knife.

"The model classification of sand mold casting can use wood molds, and the types of wood molds are different, all kinds of wood can be, but because of the difference in wood, the life of the model is also different, if you use ordinary white wood, the life is only about dozens of times, and easy to deform, the use of pine wood, its life should be about 500 times......"

In fact, the best wood for the wooden model used in sand casting is cypress, which has a service life of about 2,000 times. The reason why it is said to be the most suitable wood for mold making is because it is highly resistant to moisture, and the material is light and soft, and has strong toughness, so it is far more suitable for mold making than pine.

However, cypress is far away in Taiwan, and is not distributed in the mainland, although cypress is very widely distributed in Taiwan, and most of them are up to tens of meters of giant timber, but this kind of wood is not suitable for shipbuilding, or not suitable for manufacturing hulls, because its material is light and soft, and the hull of the artillery era requires hardwood, North American white oak and red oak are the best shipbuilding raw materials, as for cypress wood is only suitable for making decks, and it is Japan in order to replace uranium wood imports and reduce shipbuilding costs, so Taiwan cypress is used as the main material for warship decks.

"When I go to Taiwan in the future, let's use the harvested cypress wood to make molds first, and as for shipbuilding, I still have to use oak ......."

In the era of wooden sailing ships, white oak and red oak were excellent shipbuilding timber, and European warships except oak. The second wood used is Cuban mahogany and Indian teak, oak has a good advantage in addition to high hardness for warships. It's less sawdust. Of course, the harder the better, the hardness, toughness, and workability of the wood in shipbuilding should reach a balance, and oak just happens to achieve this balance. Therefore, before the steel warship, it has been widely used in the construction of warships, and in the era of wooden sailing ships, the supply of wood even restricted the development of maritime power. Just like now, if Zhu Mingzhong wants to develop the navy, he must solve the oak problem.

"You can use Mongolian oaks, I heard that the Far East is ......"

As for the Mongolian oak, it is actually the same wood as the white oak, which is very widely distributed in the coastal areas of the Far East, and the reason why I know these is because when I was in college, a roommate had a hobby of sailing, and in the chat between the two, Zhu Mingzhong learned some knowledge related to shipbuilding, and naturally also learned about wood and other knowledge.

"It seems that it's a little too far to think about this now, and the things in front of me haven't been done yet......"

Talking to himself like this in his heart, Zhu Mingzhong looked at the slowly forming wooden cannon body, after the cannon body was slowly cut and formed, and after the wooden cannon lug was added, this model would be completed, so that it could be used as a casting cannon.

After the craftsman loads the wooden model into the box, he turns the lower box over, then aligns the upper wooden mold and puts it on the lower wooden touch, then closes the sand box, and then inserts a wooden body with exhaust holes of up to 5 mm in diameter.

When the craftsmen were busy, they noticed that they were taking sand from between the two piles of sand when loading sand, so Zhu Mingzhong grabbed a handful of mixed sand from the side, and then asked Dai Cang beside him.

"Does this mixed sand seem to be different?"

"It's true."

Although the sand casting method was written by Zhu Mingzhong, in the process of testing in the weapons factory, Dai Cang had summed up some experience according to its characteristics.

"The mixed sand used now is a mixed sand made after many tests, 86% river sand, 10% clay and 4% water, and these mixed sand has its differences, divided into two types, its inner layer is made of fine sand, it is characterized by good surface quality, the surface of the casting is smooth, but the exhaust of fine sand is poor, so it can not be all fine sand, only the inner layer is about an inch thick, and the outer layer is all coarse sand, although the surface quality of coarse sand is poor, rough, but its exhaustability is good, so it is used as the outer layer, The two kinds of cast sand are mixed with thick on the outside and fine on the inside, which not only takes into account the smooth surface but also ensures the exhaust performance......"

Dai Cang's answer made Zhu Mingzhong nod and said.

"Jia Mei, I think it can be compiled into a book, so that it can be summarized in the future, such as how much sand is used, the thickness of the sand, ......and so on."

Although he does not agree with the arguments of some radical scholars in later generations that there was only technology and no science in ancient China, Zhu Mingzhong does not deny that the summary of technology in ancient China is often limited to experience, rather than scientific systematic research, just like the making of guns, everyone only knows that it is appropriate to use Fujian iron to make guns, and no one studies why Fujian iron is the most applicable, and so on. One of the reasons why it has not been able to develop into a scientific discipline.

It is precisely because of this that Zhu Mingzhong made this request at this time, and even specifically emphasized that the vernacular should be used as much as possible, and no exaggeration should be used.

“…… It must not be like the exaggerated statement in "The Divine Machine of Western Law" that "casting one hundred is the national hand", and every sentence included in the book must be based on facts. ”

"What the strategy said is that this "casting a hundred to get one, that is, for the national hand" is too exaggerated, although there are a lot of mud fan casting cannon waste, but it is not so, the following officials in Nanjing casting cannon view, casting ten can get five or six, casting one hundred get one, but it is just a boast......"

Because he understands the temper of the envoy, he knows that he hates exaggerated words such as "casting one hundred wins, that is, being a national hand", "ten miles of erosion" and so on, and even Yu Shujie was ordered by the envoy to run around the city for a whole day because of the record of "traveling thousands of miles a day" in the army, in order to verify whether he can "travel thousands of miles a day", so Dai Cang and others, although they can't play their personal literary brilliance in the book, no one wants to touch this reverse scale, lest they have to verify it like Yu Shujie.

"Unless it is to make poems and lyrics, all industries are the most taboo exaggeration, no matter all walks of life, they pay attention to the accuracy of numbers. Just like the amount of taxes, there must not be the slightest deviation......"

In his opinion, it is this kind of "literary" exaggeration that ruined ancient Chinese science and made the so-called "ancient China only have technology but no science" argument in later generations, precisely because there is almost no scientific data in those ancient scientific works, and some are just exaggerated and partial words sprinkled by literati.

Now it's time to save all this, just like mixing sand preparation, and even the weight of the wooden hammer for pounding sand has been asked by Zhu Mingzhong to record it, not just based on experience.

Experience, the experience is constantly summarized and studied, and eventually science will be formed!

After the van box is filled with mixed sand, the craftsmen use a wooden hammer to tamp and scrape the mixed sand, and then separate the upper and lower sand boxes, and then take out the upper and lower wooden models separately. After all this was done, the craftsmen carefully placed the core made of pig iron into the box.

"After a while, this core is made of iron, and a layer of fine sand half an inch thick is pressed outside......"

Because it was the first time to cast a cannon with Shafan, most of the time, Dai Cang and Xu Youzheng were both in command. Directed them to install the cross iron bolt that fixed the core above the sprue and the wooden swivel.

"After a while, the clay mold method used in the past was to first make a cylindrical core, and then make an outer model. After the core is combined, it is cast, and finally after the mouth, polishing, and drilling the fire door, a cannon is considered to be made, and the outer fan and the core are made of soil, and after slowly drying, the fan blank is hard, so the core is simple. However, the sand fan used today is relatively soft, so it requires multiple cross rods with fixed cores, and each rod needs to be connected to the sand box......"

The cross-shaped rod of the fixed core, like the exhaust body, is made of fine willow wood, which can be melted directly into the molten iron during casting, and is often the same for the 21st century, even in the 21st century. In this regard, Zhu Mingzhong nodded, and then watched the craftsman bolt the sand box to fix it, and then carefully hoisted it into a huge wooden box was placed in a seven-foot-deep soil pit, and the pouring mouth at the top of the wooden box was facing the iron groove flowing with molten iron above.

"After a while, if the sand casting method is successful, from now on, my loyal army will no longer need to consider the mud fan casting cannon!"

Xu Youzheng's tone seemed a little excited, as the head of artillery, he has always suffered from the shortage of artillery in the army, but he is not aware of the difficulty of casting artillery.

"The mud mold used in the old days can not be dried in January, if it encounters the cold weather of rain and snow in winter, and there are very few sunny days, it can not be dried in three or two months, if the mud model has not been dry, the moisture will cause the cannon body to come out of trachoma, and the casting cannon can be described as extremely time-consuming and laborious, and this sand model method, there is no such drawback......"

In fact, the advantages are not only that, Dai Cang, who once supervised the casting of cannons in Nanjing, knew very well that when he used the clay fan casting cannon in the past, he would face all kinds of problems, of course, he did not say this, after all, it was not until the cannon was cast, this sand fan casting cannon was considered a success.

"Qi Bingjing, it's time to cast!"

Dai Cang's words made Zhu Mingzhong nod and said.

"Let's cast!"

With a shout, the molten iron over there flowed out of the iron furnace, and the fiery red molten iron flowed along the casting groove to the pouring mouth at the top of the sand box, and a little heat rose from time to time into the casting hole, even at the sand box......

But it was only a moment, and more than 1,200 catties of molten iron were poured into the sand box, and after the casting was completed, Zhu Mingzhong specially ordered.

"Wait a few hours for it to cool down naturally before opening the sandbox!"