Li Qieyou rubbed his temples in great pain and sipped tea listlessly.

"Libben, are you here? But what\'s the matter?"

Yan Liben said with a smile, "Sir, I should have known about it with Tong Bing yesterday, but the disciples saw that yesterday was the day when the teacher entered the house. It\'s inconvenient to disturb, so they came to tell the teacher this morning. Sir, guess what?"

Li forgot to worry and looked at him. He suddenly stood up and said, "but the hydraulic forging machine has been built?"

"Ha ha, the teacher really guessed right. The hydraulic forging machine was completed three days ago. The disciple let the craftsman run for two days and everything was normal. Then he came to tell the teacher good news." Yan Liben was even proud that he could preside over the construction of such a magical machine. For him, it was happier than winning the lottery.

"Let\'s go and have a look." Li forgets worry and comes to the spirit.

Li forgot to worry and didn\'t call the dandies. After all, the matter still needs to be kept secret without Li Er\'s consent.

Not far from Huangyu Cuiwei palace, beside a river called Qi River, a row of workshops have sprung up.

Qi River is not wide, but the current is fast.

More than ten large water tankers with a diameter of 45 meters have been erected next to the workshop. Driven by the running river, they are rotating rapidly.

"Look, sir, this is the blast furnace for remelting private money." Yan Liben introduced various facilities in the workshop to Li forgetful.

For these iron and steel smelting, Li forget worry is that he has ten orifices and nine orifices. He knows nothing but what Yan Liben says and what he listens to.

Li also knows that up to the Tang Dynasty, steel smelting and forging technology has been very advanced. Not only the steel frying method, but also the quenching and annealing technology, as well as various very advanced steel forging technologies.

The invincibility of Tang Dao was also one of the reasons why the Tang army was invincible.

However, the blast furnace for steelmaking still uses charcoal as fuel, which makes Li forget his worries. He vaguely remembers that it seems that coke was used as the fuel for steelmaking in the late Southern Song Dynasty.

Coke is used to make steel, with higher furnace temperature and better quality of molten steel.

However, coke must be secondary processed from coal. Li forgetful only knows about this, so he is not in a hurry to raise the matter with Yan Liben.

Piles of private money were put into the blast furnace and slowly melted into a furnace of copper water under the continuous heating of carbon fire.

The craftsmen poured copper water into the mold and waited for it to cool.

"This is to cast copper water into copper bars as thick as copper coins. After the copper bars are cooled, they can be sent out of the hydraulic casting machine and stamped into copper coins."

Yan Liben proudly invited Li Qieyou to a huge forging hammer: "Sir, this is a hydraulic forging machine made according to your drawing. It\'s very good. Looking at the hammer head, it weighs 20 stones and is made of pure steel. It\'s extremely powerful. Driven by the water wheel, it can be hammered twice a minute day and night."

Li forgot to worry. Twenty stones are two thousand kilograms. A ton of hammer head is really great in Datang.

What Yan Liben said is not a minute for future generations.

The Tang Dynasty inherited the Daye calendar of the Sui Dynasty. A tool called leaky carving is used for accurate timing.

That is, a tool for timing by dripping water. A day is divided into twelve hours. Each hour is 500 minutes, and one minute is equivalent to 14 seconds.

In other words, this one ton hydraulic forging machine can beat eight times a minute, which is very good.

Li Qieyou asked curiously, "libben, how do you solve the problem of hammer swing?"

The biggest problem of this original hydraulic forging machine is the poor hammering accuracy, which is difficult to carry out fine processing like the forging machines of later generations. After all, it is normal for the hammer head to swing left and right in a certain range every time it rises and falls.

However, to punch and forge copper coins, the hammer head must fall on the same point every time.

Li forgot to worry because he didn\'t know how to solve this problem, so he simply became the shopkeeper and threw it all to Yan Liben.

Yan Liben was very proud and pointed to the thick lever connecting the hammer head.

"Sir, I made a device here to connect the lever and let it slide into the funnel-shaped hole when it falls, so as to ensure that the hammer head falls in the same position every time."

Li forgot to worry about it carefully for a long time, and then he probably understood Yan Liben\'s design. He couldn\'t help raising his thumb towards Yan Liben.

Great, really great.

Who said that the ancients were not smart? Li forgot to worry about making this device by himself. He certainly couldn\'t think of it.

Yan Liben smiled a little embarrassed when he was praised by his teacher. In his opinion, these are mainly Li\'s ideas. He just realizes the teacher\'s design.

However, Yan Liben was very happy to get the teacher\'s affirmation. He pointed to the craftsman busy in front of the forging machine and said: "Look, sir, the hammer head and the base below are all stamping molds made of fine steel. The craftsman puts the cast copper bar on the mold, and when the hammer head falls down, a good copper coin will be cast. Compared with the past coin casting, it is much simpler, and only one craftsman can manipulate it. I really admire you, sir 。”

Li forgot to worry, but his face was not red and his heart did not jump. He accepted Yan Liben\'s praise. Anyway, he was used to being so "flattered", and his face became thicker and thicker.

He was forced to nod and smile, watching the craftsman mint coins.

With the water flow driving the waterwheel to rotate, the hammer head was raised high, and then fell heavily. With a loud bang, it accurately hit the copper bar below.

The hammer head slowly raised again, and a copper coin with metallic luster fell into the bamboo basket containing copper coins below, making a crisp and pleasant sound.

Li Qieyou reached out and picked up the freshly baked copper coin. The words "Kaiyuan Tongbao" were dense, clear and powerful.

These four characters are not written by ordinary people, but by Ouyang Xun, a master of calligraphy.

Li forgot to worry and took out an official money from his money bag for comparison.

The two coins are of the same weight, but different from the cast copper coins, the stamped copper coins are more fine and metallic.

If you have to choose an official coin from these two coins, Li Qieyou believes that most people will choose the stamped coin.

"How many presses have been built?"

"There are already ten, and others are still under construction."

Li QIAOYOU calculated silently that a hydraulic press can beat eight times a minute, that is, to make eight copper coins.

One hour is 480 coins. If three shifts do not stop working in a day, more than 5700 copper coins can be suppressed. Ten sets can make 57 copper coins in a day.

This is a big gap from the original boast that he and Li Er could make thousands of copper coins a day.

However, this hydraulic forging machine can continue to be expanded. If there are 100 sets, it can produce more than 500 copper coins per day. If there are 200 sets, it is not a problem to produce thousands of copper coins per day.

"Ha ha, Liben, you\'ve done better than you thought as a teacher. Niu Wu, take my goldfish talisman and go to Taiji palace to find Mituo. Let him tell the sage that coinage is done. See if the sage wants to check it himself. Go back quickly and I\'ll wait for you here."

"Promise!" Niu Wu did not hesitate, took Li forgetful\'s goldfish charm and ran outside the workshop