Fang Er was very careful with this thing; it was prone to explosion.
With a boom, it ignited directly, flames shooting out a meter from the furnace opening, then retracting.
Fang Er went into an adjacent room, using its cover to retrieve a pile of hardware tools from his system space.
Wrenches, screwdrivers, and such; he wouldn't need them anyway, so melting them down was perfect. He kept two of each just in case, then took out the rest, placing them in a basket and carrying them to the furnace.
"Brother Fang, what are these things? Why are their shapes so strange?"
Wei Chi Bao Lin asked, looking at the pile of items in the basket.
"I don't know. I found them some days ago. I thought the material was good. I don't know what they're for, and we don't have any ore now. It's better to melt these down and make something."
Fang Er lied, and Wei Chi Bao Lin didn't pry.
The furnace's temperature grew higher and higher.
Fang Er carefully heated the crucible with tongs.
He had examined the crucible closely. It was a top-quality graphite crucible, and he wondered where Wei Chi Gong had obtained it.
Graphite was the best material for crucibles, with a melting point of over three thousand degrees Celsius. Iron and steel's melting points were only a little over a thousand degrees, which was more than enough.
This thing needed to be heated slowly; it couldn't be placed directly on the furnace, or it would significantly affect the crucible's lifespan. He couldn't bear to damage it.
Slowly, the crucible's color began to change.
Fang Er placed the crucible in the center of the furnace and put the tools into it one by one.
From time to time, he would lift the crucible and add charcoal and charcoal powder to the furnace.
The function of charcoal was self-evident.
Charcoal powder, due to its small volume, burned more completely, maximizing the furnace's temperature.
After about half an hour, the crucible turned fiery red, and the items inside had all become liquid.
But looking at the pot of molten steel, Fang Er became troubled.
This was also due to insufficient preparation; there was nothing suitable for stirring.
Normally, a graphite rod should be used for stirring to help expel impurities, but he didn't have one.
Fang Er scanned his surroundings but couldn't find anything suitable to use as a stirring tool.
Finally, his gaze settled on Cheng Chu Mo's waist-worn saber.
"Chu Mo, come, give me your saber."
Fang Er reached out and said.
Cheng Chu Mo didn't ask why, directly taking it off and placing it in Fang Er's hand.
Fang Er tossed the scabbard aside, gripped the hilt with both hands, and inserted the blade into the crucible, stirring back and forth.
As the molten steel was agitated, a stream of bubbles rose to the surface, carrying some black impurities with them.
When Fang Er drew the saber out, only half of it remained.
Cheng Chu Mo was dumbfounded.
This saber was his beloved weapon.
He was rarely without it, and his father had often beaten him for it, neglecting the family's heirloom tripartite axes and horse lances to practice inferior saber techniques.
"Hahaha, Chu Mo, your saber is gone this time. It's better to go home and properly learn the horse lance."
Wei Chi Bao Lin teased from the side.
"Bao Lin is right. Saber techniques are suitable for one-on-one combat, but on the battlefield, the horse lance is better. Here, I'll make you a spearhead. Go back and find your father to get a shaft and attach it, how about that?"
Hearing Wei Chi Bao Lin's words, Fang Er had an idea.
He hadn't planned what to forge, but now he could make a spearhead for each of them, which would also serve as a gift.
In this era, many generals used horse lances. Generals like Cheng Yao Jin, Wei Chi Gong, Li Cun Xiao, and even Qin Qiong used horse lances as their primary weapons when fighting on horseback. However, forging a good horse lance was extremely troublesome; the shaft alone required three years to make.
But as families of generals, they usually organized artisans to make spear shafts annually, ready for any eventuality.
"Brother Fang, you can't play favorites, don't forget me!"
Wei Chi Bao Lin, seeing Fang Er offer to forge a spearhead for Cheng Chu Mo, immediately became anxious.
"Don't worry. This pot has thirty to forty jin of steel. It's enough to forge a spearhead for each of you,"
Fang Er said with a smile.
The molten steel still needed high-temperature forging for a while to expel impurities and needed to be maintained in a liquid state for even mixing.
Fang Er placed the crucible on the furnace and instructed Zhu Zi to keep an eye on the heat.
While this was happening, he made four identical molds using red clay.
He then sprinkled a uniform layer of very fine wood shavings into the molds. This was waste material from making the waterwheel, which was perfect for use.
Afterward, he fitted the molds together in pairs, forming a complete, hollow mold.
Due to time constraints, Fang Er skipped the air-drying step, as they would need to be refined later anyway.
He had Wei Chi Bao Lin fetch two buckets of water, into which he added a large amount of refined salt, preparing it for quenching. Since there wasn't a large enough container, even Fang Er's bathing tub was brought out.
Using the tongs to grip the crucible, he carefully poured the molten steel into the molds. Once the temperature cooled to a certain extent, he broke the clay molds, revealing two dark spearheads before them.
The reason Fang Er sprinkled wood shavings in the molds was deliberate. As the molten steel entered the molds, the intense heat caused the wood shavings to rapidly oxidize, and the carbon would then seep into the outer layer of the spearheads.
Hardware tools like screwdrivers were often made of low-carbon steel, which had good toughness but lacked hardness.
With this treatment, the interior would be low-carbon steel, while the exterior would be high-carbon steel, achieving a balance of overall toughness and hardness.
Furthermore, after sharpening, they would be even sharper!
However, the flaw was that because the molds were wet, as the molten steel poured in, the water evaporated rapidly, causing cracks to appear in the molds. Consequently, both spearheads had scar-like protrusions to varying degrees.
Using the tongs to grip the spearheads, he directly threw them into the bathing tub.
Ssssssh~!
Dense steam immediately rose from the bathing tub.
After a while, Fang Er fished the spearheads out of the tub. Upon inspection, the scar-like protrusions were actually quite distinctive, and he had an idea.
He set the crucible aside, returned to the house, and retrieved a two-centimeter diameter drill bit, which was part of a modern impact drill. Looking at the remaining items, he found two adjustable wrenches and decided to take them as well.
Returning to the courtyard, he held them with the tongs and placed them at the furnace opening to heat until they were red-hot. Using an adjustable wrench to secure the square position at the tail of the drill bit, he handed it to Cheng Chu Mo to hold.
He then adjusted the jaw opening of another wrench and clamped it to the other end of the drill bit.
"Come, twist hard, in the opposite direction of this drill bit's thread, like this."
Fang Er called Wei Chi Bao Lin over, demonstrated, and then handed him the wrench.
"Simple, watch me. Chu Mo, hold on tight! Hey!"
After Wei Chi Bao Lin spoke, he exerted force, and the screw-shaped drill bit was turned back partially in the opposite direction.