Four days later, the backyard of the North Slope Mine firing room.
Two deep holes were dug in the ground in the yard, each hole was round, narrow at the top and wide at the bottom. The inner diameter of the front section is about 20 cm, and the inner diameter of the rear end is expanded to 26 cm. These holes are the molds that Roland intends to use to cast the cannon embryos. The inner walls of the holes have been baked by Anna, and the surface soil is sintered into a whole, as if a layer of shell is attached. The medicine chamber is facing downwards to obtain better wall quality when casting, and the higher it is, the more scum and air bubbles it contains. The dimensions of all the caves were calculated from the cannonballs. He roughly remembered that the so-called six-pounder and eight-pounder guns in history were named after the weight of the cannonball. The inner diameter of the mold is calculated by adding the ball diameter and the wall thickness of the gun tube.
In the absence of measuring tools, Roland simply customized the standard. He intercepted a piece of iron strip about the width of his ring finger as the base unit, one centimeter, and then made iron strips of other sizes and engraved the points. segment line.
The diameter of the twelve-pound iron ball is about twelve centimeters when measured by a crude iron ruler. He set the thickness of the pipe wall at the thinnest point at four centimeters. , thereby obtaining the inner diameter of the mold. As for the length, although he knew that the artillery had a double diameter, he was only impressed by the double diameter of the main guns of the battleships and the main station tanks. As for the antique front-mounted guns, he really didn't know.
Considering that the shorter the body tube, the lighter the weight, and the more material saving, Roland waved his hand and took the value of one meter five. If the test shot effect is not satisfactory, you can adjust it later.
When the artillery was first invented, iron bars were placed on the wooden core material and iron powder was added to the mouth, and then the iron hoop was used to reinforce the core material in the gun chamber, just like the storage of wooden barrels. Of course, Roland knew that this kind of artillery had the risk of air leakage and explosion, so he directly adopted the process of integral casting and boring machine drilling. For a steam boring machine, whether it is a six-pounder or a twelve-pounder, there is no essential difference in difficulty.
In line with the idea that caliber is justice, he naturally chose a 12-pounder gun with a larger muzzle and a thicker barrel. Further up, it is not easy to use as a field gun. It doesn't matter whether the weight of the shell is calculated as a shot put or an iron ball, as long as it can be shot. After all, he is borrowing from history, not playing with replica models.
"Let's start," Roland took a deep breath and said to Anna. The latter nodded, grabbed a steel ingot, and hung it above the hole. The green flame ignited, the steel ingot quickly turned red, and then melted, forming a small waterfall of molten steel that flowed into the hole. The surface of the molten steel is reddish-orange, and the inner core becomes incandescent, the brightness of which is hard to see. In order to protect the witch's eyesight, Roland also specially set up a support at the entrance of the hole. She only needed to determine the position in advance and put her arm on the support pad, so she didn't need to stare at the molten steel to see if it flowed into the hole.
These steel ingots are usually accumulated slowly. Anna alone cannot start the era of large-scale steelmaking, but small batch production is not a problem for her. After the most difficult temperature level is solved, use the method of frying steel. Better quality steel can be obtained.
This is why Roland dared to customize the barrel size. Compared to cast iron barrels and bronze barrels, cast steel barrels are obviously stronger. Even if the size is wrong, the gun will not blow up easily.
The molten steel is gradually rising, and the steel ingots that have been saved are also rapidly decreasing, which makes Roland feel a little heartache. When will he wait until he can build a pile of chimneys and blast furnaces on the territory to make endless steel? For a long time, steel production was one of the criteria for measuring the strength of the great powers, and he now felt it personally.
Filling the two molds, Anna's cheeks turned bright red. Roland took out a handkerchief and gently wiped the sweat from the tip of her nose. At first, Anna would show a little resistance, but now she is obediently motionless, closing her eyes and letting Roland do it.
The drooping bangs are dyed with a red edge under the reflection of the molten steel, and the soft neck makes people want to take a bite. When he is condescending, the other side's half slender collarbone exposed through the collar will enter his field of vision. As she got closer, she could still smell the faint fragrance coming from her body.
"Cough, okay..." Roland put away the handkerchief, and at the same time withdrew his eager emotions, "Let's be here today. Well done, I will ask the kitchen to reward you with an extra black pepper steak for dinner."
Not yet, he thought, and doing so would inevitably lead to the suspicion of taking advantage of others. Just wait until she is truly free...
Anna opened her eyes, and although the sweat had been wiped away, her face seemed to be even redder than before. She nodded to Roland and replied softly, um.
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For the next few days, Roland traveled back and forth between the castle and the North Slope Mine.
In addition to the barrel, he also needs to make a sufficient amount of boring tools.
This tool for drilling is made in a similar way to a gun barrel. Its diameter is exactly the same as that of a projectile. After taking it out of the mold, Anna heats it again and uses a hammer to shape it. It is very different from the ordinary spiral knife in appearance. At first glance, it looks like a blunt iron rod. The only difference is a notch on the top of the head to let out metal chips. The last is quenching to improve the hardness of the boring tool.
Unlike the high-precision drill bits of modern boring machines, Roland only needs an iron rod that can punch holes. Considering the high wear rate, he and Anna made five simple boring tools in one week. Before this, the steam boring machine has fully verified its ability - the production of pig iron barrels has rapidly increased from two per month to ten per day.
When everything is ready, the cannon embryos are dug out from the earth pit by miners, and after cleaning the surface scum, they are carried on a carriage and transported to the blacksmith shop.
These two cannon embryos almost consumed all the steel that Roland had accumulated, which is not an exaggeration to say that they are priceless. During the transportation, the prince ordered Carter and two knights to be in charge of the whole process, which made the chief knight feel a little unnecessary. Who would steal such a dead thing
The blacksmiths leveled and polished the surface of the cannon shell according to the prince's request, and after grinding it with the grindstone, it was sent to the backyard of the castle without stopping. At this moment, the two round solid steel rods turned dark gray on the outside, exuding a heavy metallic luster.
Roland couldn't wait to replace the boring tool, and together with Carter, he fixed the blank in place so that the top of the cutter head just pressed against the center of the steel bar.
Facing this historic moment, Roland pulled the valve of the steam engine. The boring tool starts to run slowly, and it doesn't take long for it to rise to a steady speed.
"Into the knife!" cried the prince.
The chief knight pushed the sliding base to control the depth of contact between the gun blank and the boring tool, and when the blade touched the barrel, the screeching noise instantly overshadowed the roar of the steam engine. Lard, which acts as a lubricant, is squeezed into the drilled holes, and black foam and twisted wires emerge. The witches onlookers retreated from the wooden shed one after another, and only Lightning remained in place. It seemed to her that these dark machines were more beautiful than any scenery.