chapter 39
02. A visitor from the future (14)
Beep beep beep-
Tak.
It’s 2:40 in the morning. I wake up at the same time today.
“Hmm.”
Today is August 16th.
It is the day before the day of the person who will finish the three-person sword.
I drive away sleep by stretching, and after simply washing my face, I head to the studio with a clear mind.
More than half of summer vacation has passed.
In the meantime, I’ve been making three-person swords, and I’ve spent my daily life without anything special happening.
I’ve never met Yoon Seo-hee because she’s always busy during her vacation, but I heard that she goes with Baek Ji-soo from evening until the morning sun rises.
Even if we reach her during the day, she looks very sleepy and tired, so she didn’t want to disturb her.
She didn’t have any friends to contact, except for occasional calls from Lee Byung-jun asking how she was doing, and since she continued to live a different life day and night, during vacation she really only repeated making swords. Did.
Until now, my summer vacation has always felt like this, so I didn’t have any complaints or impressions.
… No, to be honest, it was a bit disappointing.
Until now, no one bothered to make friends with a geek like me, so I took it for granted that I was alone.
But after making friends, I stopped taking being alone for granted.
No matter what, Yoon Seo-hee was always paying attention to me, and after I became close with Lee Byung-joon, she started talking to me so often that there was no time to be bored.
“Huh, true.”
I heard that people usually look forward to summer vacation.
I’m waiting for the vacation to end.
I decided to get rid of my thoughts by making a sword.
I go down to the studio and check the results of the work I did until dawn yesterday.
The finished ink-colored blade sparkles even in the dark underground workshop, shining the starlight unique to star ore.
Including the tang, the total length is about 1m, and the blade is about 70cm long.
Because everything has been polished, the blade is sharp like a razor. It was a perfection that felt worthwhile after grinding for a long time.
On both sides of the ink-colored black surface, the Big Dipper and the Mantra were carved with a chisel in advance. On the last day, it will be inlaid with gold threads along these cut grooves.
But before that, I’ll have to finish the hardening I’ve been putting off.
Tomorrow was the final stage of assembling the sword, so actually making the sword had to be finished today.
Flame! When the fire is lit, the heat in the workshop heats up.
I inserted the blade into the blazing fire.
After vigorously stirring the coals to distribute the heat evenly, fill the soaking tub with water while waiting for the blade to heat up.
Clear and clean water filled up the soaking tank.
This time, oil is not used like when making golden eggs.
I’m going to try water soaking today.
‘I don’t know if it will turn out well.’
From the Goryeo to the Joseon Dynasty, Korean swords were traditionally quenched with water, so it was decided to use water for quenching the Samin sword.
Quenching is the most difficult and careful process in sword making, but if you use water instead of oil, the difficulty doubles.
The speed at which hot metal is cooled when it is put into water is incomparable to that of oil.
Because the metal cools at a rapid rate, the probability of cracking, a phenomenon in which the sword is bent or broken, is too high as the inside, which has been expanded to the fullest due to heat, shrinks.
But if you use it well, it will make a sword much harder than if you used oil.
This is because the faster the cooling rate, the closer the iron grains become to martensite.
Steel structure can be classified into austenite, ferrite, cementite, pearlite, martensite, etc., And in simple words, it is a classification of internal crystals according to the carbon content and temperature of iron.
Martensite has the highest hardness among steel structures.
Its hardness is such that even a diamond can be processed.
So, quenching in water is an effective way to increase the strength of a sword at once as much as it is difficult.
I opened my eyes wide and watched the color of the blade heating up in the roaring flames.
The vivid orange color close to red meant that the surface temperature of the metal had risen to over 1,000 degrees Celsius.
I had to get it out right now. Grasp the blade with tongs and pull it out of the furnace.
“Whoa….”
I’ve made countless swords, but I’m always nervous at this moment.
For quenching, the temperature of the water must be maintained at about 20 to 30 degrees and the surface temperature of the metal must be precisely adjusted.
Even if the temperature is adjusted, the metal can be cracked or cracked with just the slight impact of immersing the blade in water. This is because the metal is the most vulnerable moment because the internal structure is rapidly deformed.
Quenching is a collection of variables.
No matter how carefully and meticulously prepared you are, even if you are a master among craftsmen with a lot of experience, failure happens in an instant.
I put the knife into the water without hesitation.
“Suck!”
Chiik-! White smoke rises with the sound of metal cooling.
Ting even if you listen! Do it or do it! No sound is heard
I took the knife out of the water and checked it.
This meant that the quenching was successful without any problems.
“Whew….”
I caught my breath, clenching my fists in relief.
Water quenching is a highly advanced task that requires even a skilled artisan to be prepared to break a knife. After finishing it without any problems, I naturally felt the tension release.
Of course, this is not the end.
The martensitic structure after quenching is hard, but it is easily broken by impact due to its high hardness.
In order to give proper toughness, it was necessary to temper.
I put the tempered blade back into the furnace.
Flame! The ink-colored blade begins to rapidly heat up in the hot flames.
This time I took the blade out when it was a lighter color rather than waiting for it to turn orange.
The surface temperature is about 550 degrees. I placed the heated blade on the anvil.
In this state, the metal that has been reheated to an appropriate temperature is air-cooled. It is slowly cooled in the air without being immersed in water or oil.
Through this process, a hard and flexible sword with toughness and ductility is completed, even though the hardness may be slightly lowered.
‘It’s been going well so far.’
I turned off the fire in the brazier and wiped off the drenched sweat.
There is still a little bit left until 5:00 in the morning, but we needed plenty of time for tempering, so we decided to finish today’s work here.
Over the past 15 days, all preparations have been completed, including the nose, hilt, and gold thread for inlay.
It was a worthwhile pace of progress as I worked every single day to somehow meet the deadline.
“Whoa.”
After getting out of the steamer in midsummer, I took a breather and went up to the living room, where the light was on even though it was early.
My grandfather was sitting at the living room table drinking tea.
“Grandpa? Are you up already?”
“Come. Did you have a hard time in the heat? Have some iced tea.”
His grandfather served cold green tea as if he had waited.
“Thank you. I will drink well.”
Because I was in front of the fire, I was still thirsty, so I decided to receive it with a grateful heart.
As she drinks the iced tea at once, a cool refreshing feeling runs down her throat.
I think I’ll buy some now.
“You woke up early today.”
“Heh heh, I have something to say to my grandson.”
“… ?”
Since I was sweating profusely, I held back the urge to take a shower right away and calmly sat across from my grandfather. Because the atmosphere seemed somehow unusual.
“How about it, do you think the three-person sword will be made well?”
“Yes. I finished the tempering today, and I’m going to assemble the hilt tomorrow. It will probably be over by tomorrow.”
“It is very difficult to make traditional Hwando. Still, I’m happy to see Lee Jin trying to make it the old way.”
“Of course. Whose grandson are you?”
I answered with a shy smile.
My grandfather was once an artisan who made traditional swords.
Of course, it was a long time ago. In order to take care of the one remaining grandson after losing a child early, the grandfather had to give up his blacksmith job where he had to stand in front of a fire all day.
But most of my skills I learned from my grandfather.
I inherited the workshop as well as the one I used in the past, and my grandfather directly taught me the knowledge needed to make a three-person sword.
“Have you finished making red joshua?”
“Yes. I already made it.”
“What is the material?”
“Uh, I just used regular yarn.”
Hongjosua refers to the decorative thread that is hung from the hilt of a sword, originally called yuso. Hwando’s Yuso often wore red, so he was usually called Hongjosua.
The reason for decoration is great, but it is not really useless, and it is also used to tie the sword to the wrist so as not to miss it during battle.
But it doesn’t have any symbolism, so I just made it properly using normal thread. It was because I didn’t have enough time to care about that part.
“Then why don’t you try this out?”
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Grandpa with a gentle smile placed a ball of thread the size of his fist on the table.
For an ordinary thread, even at a glance, I felt unusual magic.
Could it be something from the tower?
“What is this?”
“It’s your father’s stuff.”
“… Yeah!?”
I gasped in surprise.
Your father’s stuff?
“I thought about it for the first time in a while and looked it up and found something like this. I brought it because I thought it might help you make a sword.”
“No, Grandpa….”
I didn’t say anything because I knew what my father’s belongings meant to my grandfather.
It’s been more than ten years since the two of them passed away, but my grandfather still hasn’t sorted out his belongings.
It’s to the point that my parents’ room is still in the same state as it was before I climbed the tower for the last time, as if time had stopped.
That’s why I don’t carelessly touch my parents’ things.
It was because he knew how much his grandfather treasured the keepsakes of the two of them, so he didn’t feel like touching them.
“I don’t know exactly what this is. But since it’s something your son left behind, it would be the right thing for Lee Jin to pass it on to you.”
“… Can I really take it?”
“Of course not. It’s your father’s.”
I carefully held the ball of thread in my hand.
It seemed that it was not an ordinary thing to feel fluffy and soft yet strong magical power.
“Thank you. I will write well, Grandpa.”
“Yes, you must be tired, did I hold on too much? Just go upstairs and rest.”
“Yes. Grandpa, get some more sleep.”
The sun hasn’t risen in the morning yet. It was early for the day to begin.
But Grandpa shook his head slowly.
“No. When you get old, you lose sleep and only feel sentimental. Grandpa will stay here a little longer.”
Now that you’ve said that much, I couldn’t recommend it any more, so I bowed my head and went up to my room.
The last time I saw my grandfather’s expression, he seemed to be thinking back to the distant past.