Jiajing actually gave the Heiyanshan Coal Mine to Lu Ling'er. Yang Cong did not expect that. He just wanted to give Chen Hong some eye medicine so that Chen Hong would take the opportunity to install his own people next time when Jiajing sent a mining supervisor. Unexpectedly, he would get such a big advantage in vain.

Although coal is not valuable at this moment, it is just that there are few people to use it. In fact, the value of coal is not much different from that of later generations. A coal mine is worth hundreds of thousands of taels of silver. If the reserves are large, it is possible to be worth millions of taels. Giving it to Lu Ling'er is actually equivalent to giving it to him.

It's such a big cheap, so he immediately arranged for the Yang family shopkeeper to take over the Heiyanshan Coal Mine. As for the next mining, it would be very hard to dig. Anyway, the coal dug will definitely be used in the future.

Jiajing's move also proves one thing that he attaches great importance to the manufacturing of weapons and equipment in Xuanfu Town, and there is definitely no problem in mining copper mines.

Yang Cong immediately submitted a memorial to open the Akagi Copper Mine. In the memorial, he also explained the reason for opening the Akagi Copper Mine.

However, he did not explain too much. He did not say anything about the development of post-engineering guns. He just said that the processing of iron guns is too difficult. If we want to manufacture guns and cannons equipped with 60,000 elite border troops, it will take at least twenty years. Only by replacing them with copper guns and cannons can it be completed within four or five years.

He believed that Jiajing would definitely not be willing to wait for more than 20 years, and there was definitely no problem in mining the Chicheng copper mine, just not knowing who Jiajing would send to be a mining prison.

Next, it will take at least half a month to wait for the mine supervisor to mine copper ore and prepare to smel bronze. Yang Cong naturally cannot be idle. There is no copper ore at this moment. It should be no problem to find some ready-made copper to make a new musket sample first. He focused his energy on the development of the new musket.

Since the front barrel has been changed to copper, the latter parts are naturally better, so the production efficiency will be higher. After thinking for a while, he simply changed the latter parts, not only were they changed to copper, but even the threads and other things were added. He even "designed" the bayonet mechanism in the front.

Originally, he thought it would be very simple to find some copper to make a sample, but he never thought that several shopkeepers of the Yang family sent them out and searched for a few days, but they still couldn't find any copper yet!

There are no copper ingots on the market these days. The imperial court has strict control. In the end, a shopkeeper had an idea and went to a nearby temple for a walk. He spent more than ten taels of silver to buy a scrap copper cauldron weighing more than 100 kilograms.

This copper tripod is used to provide incense. I don’t know what happened, but it broke a gap. Yang Cong looked at the copper tripod about a foot in front of him, and was so amazed and laughed.

It's really not easy to make something these days.

Fortunately, whether it is a copper tripod or a copper ingot, there is finally a copper. Moreover, Wang Xuan ordered people to change the furnace for smelting the copper mine during this period. As long as the copper tripod is smashed into pieces and throw it in, it will be done.

Next are the processes of making wood molds, sand molding, casting, drilling, etc. With the previous experience, Yang Cong does not need to be guided every step this time. The craftsmen are still very professional at this time. As long as they do it once, they will know it without repeated training.

This is indeed much easier to process than cast iron parts. Even if a three or four-foot-long barrel is drilled, it is not that difficult to drill holes. The two craftsmen work together to brush and brush, and the holes will be drilled in less than an hour. Of course, there are quite a few holes left in the middle when the barrel is cast, which is not solid. Strictly speaking, the drilling holes behind can only be considered reaming. If you really drill a hole on a solid copper rod, it will not be so easy to drill.

At this moment, Wang Xuan also processed the reamer according to Yang Cong's instructions, and the most time-consuming process of grinding the inner hole was also solved. The production speed of the new musket seemed to be much faster. In less than half a day, all the parts were processed almost the same.

However, at the last step, it got stuck again.

This step is to add threads between the front and rear barrels, one external thread and one internal thread, and only two threads in total. If it were later, even if it was used to process the most backward plate teeth and taps, it would take a few minutes. However, there were no plate teeth and taps at this moment, so they could only be chiseled out by hand and grind out!

Threads seem simple, but hand-processing is not that easy. Even if they are made of wooden, it is difficult to process them, let alone copper.

The external thread is a little better. At least it can be seen, and it is more convenient to process it. The internal thread is different. Not to mention the inconvenient viewing angle, it is very difficult to process it. Several skilled craftsmen worked hard for a long time and only processed the external thread of the front barrel, but they had no way to do the internal thread of the rear barrel, because the barrel is made of copper, not wood, and they can't pick it up at all!

Yang Cong looked at the craftsman using a pointed chisel to try to chisel the inner wall of the gun barrel but couldn't use it any force, and his brows frowned again.

This is definitely not possible. Even if these craftsmen can come up with a way to pick out the internal threads, because the efficiency is too low, and the speed of using manual processing of threads is so slow that it is simply unbearable and there is no efficiency at all.

At this moment, he had to order people to get charcoal pens and manuscript paper, draw drawings of the teeth and taps, and let Wang Xuan find a way to do it.

Wang Xuan encountered the same problem when processing plate teeth and taps. It’s a bit better to say that the taps are also external threads. Even if they are replaced with iron, they can be processed after a little time. The plate teeth are troublesome. There are internal threads and copper internal threads cannot be processed at this moment, let alone iron internal threads.

Yang Cong looked at the iron lump that could not be clenched no matter how hard he picked it, and his head was big. What should he do? This seems to be a vicious cycle. Anyway, he just can't process the internal threads on the metal at this moment.

He racked his brains and finally came up with a solution, which was to dig the plate teeth from the middle and divide them into two halves, so that the threads would be exposed outside, making it more convenient to process. After processing, use rivets to rivet the two sides together, and the effect would be similar.

In this way, it is easy to process, but the thread connection is prone to problems. As long as the thread is slightly inconsistent, it will not be screwed in at all.

There is no good idea for Yang Cong. At this stage, he can only rely on the intelligence of craftsmen to solve this problem.

Not to mention, if it is purely more than handicrafts, the craftsmen at this time were much better than those of later generations. They could even carve lifelike dragons, phoenixes, unicorns, etc., so the rigid threads naturally could not help them.

Several old craftsmen thought about it for a while and soon came up with the solution.

In fact, the method is very simple, which is to heat the teeth on both sides, burn them red, and then press them on the cold tap at the same time. As long as the force is enough, the thread marks will always be pressed out on it. Then follow the pressed marks, and the threads on both sides will basically meet.
Chapter completed!