1950s: After transmigrating into a capitalist, I relied on military industry to achieve a comeback.

"No, Master..."

Lu Zheng held up a freshly drawn blueprint, his brows furrowed deeply. He stared at the complex surface parameters on the blueprint, then ran his fingers through his hair a couple of times.

"The curve of this impeller you drew is just too bizarre. That curvature, that angle—it must have required milling it out bit by bit with a five-axis CNC machine tool! Our old German boring machine in the institute can only handle three axes at most. This… this is simply impossible to cut!"

"Who said we were going to use a machine tool?" Lin Jiaoyue looked up from a pile of scrap parts that smelled of machine oil. Her wrists were a little sore from drawing for a long time, so she rubbed them a couple of times and gestured with her chin toward the corner of the wall. "Use that one."

"Use...use that?" Lu Zheng followed her gaze, his voice cracking, "Isn't that the old furnace we use to fire refractory bricks?"

"It used to be, but it's not anymore." Lin Jiaoyue pulled out a rag to wipe her hands, a slight smile playing on her lips. "I call it 'precision casting'."

Seeing Lu Zheng's blank face, Lin Jiaoyue didn't keep him in suspense any longer. She reached out and broke off a small piece of solidified yellow wax from the corner of the table, kneading it between her fingertips:

"It's very simple. First, we use wax to sculpt a one-to-one model of the impeller. Then, we coat the wax model with a special quartz mortar. Once the mortar has dried and hardened, we throw it directly into the furnace to fire."

She casually pressed the piece of yellow wax between her fingers onto the table:

"When baked at high temperatures, the wax inside melts into water and flows out, leaving a perfectly precise cavity inside the hard outer mortar shell, right?"

Lu Zheng's mouth was agape in an "O" shape, and he couldn't close it for a long time.

"Finally," Lin Jiaoyue picked up the enamel mug on the table, pretending to pour water, "pour the molten steel from the converter directly into this cavity. After it cools, smash the outer mortar shell... and you'll have a perfect impeller, saving you the trouble of polishing!"

This "lost-wax casting" method is actually a technique that our Chinese ancestors used back in the Bronze Age, but its transmission gradually ceased. What Lin Jiaoyue is doing now is incorporating the coefficient of thermal expansion and contraction from modern materials science, completing a groundbreaking replication.

But to Lu Zheng, this was as absurd as hearing someone say in the middle of the night that the Black and White Impermanence had come to work.

"Use...use wax to make a mold?" Lu Zheng's eyes widened, and he waved his hands repeatedly. "Master, don't be ridiculous! Pouring molten steel at over a thousand degrees Celsius in there would just cause the shell to explode!"

"Therefore, we have to use a special quartz sand mortar to make the outer shell."

"What about precision!" Lu Zheng slapped his thigh anxiously. "If the impeller is off by even a fraction of a second, the pump's efficiency will drop by half! Can a hand-molded block of wax be as precise as the cutting edge of a German machine tool?"

"Don't worry, I've already calculated the ratio of the quartz sand and the expansion and contraction rate of the wax."

Lin Jiaoyue didn't explain further, but simply reached out and patted Lu Zheng's stiff shoulder.

"Go and call all the fitters and carpenters in the workshop who are at least level eight or above, those with the most steady hands. I'll teach you how to 'play with mud.'"

Half an hour later, an extremely strange scene unfolded in Workshop No. 2 of Institute 909.

Six or seven veteran craftsmen, with an average tenure of over twenty years, sat around a long table, looking at each other in bewilderment. There were no files or calipers on the table, only a pile of limp yellow wax and several basins of dusty mortar.

"Mr. Lin, is this... really going to work?"

Old fitter Master Li held a piece of wax the size of a walnut, his muscles taut, even the veins on his neck bulging. He had spent his whole life wielding a heavy hammer and battling steel, his calluses as thick as cowhide, and when he used a file, he could control the error to within a hair's breadth.

But now, holding this soft, yielding piece of wax that would deform with the slightest pressure, his large hands, capable of bending steel bars with his bare hands, were trembling uncontrollably.

He held his breath and, following the curve on the drawing, pressed his thumb down with just half an inch of force.

A crisp "click" sounded.

The wax piece didn't even bend; it was crushed in two by his brute force and fell onto the table.

Master Li's face flushed red from his neck to his ears. He hurriedly covered the broken pieces of wax with his palms, and his rough hands rubbed them hard on his oil-stained canvas apron. Beads of sweat dripped down his forehead and down his wrinkles.

"Ouch, this thing... this thing doesn't hold up! It deflates as soon as I squeeze it!"

"Don't rush, soften your grip, don't treat it like a lump of iron." Lin Jiaoyue didn't laugh, picked up a small carving knife, and smoothly carved a smooth arc on the wax block. "Tone down the hardness you usually have when you're fighting steel."

For the next three days, these top craftsmen were driven nearly mad by the mud and wax blocks. Either the wax molds were uneven in thickness, or they deformed the molds by applying too much force when applying the mortar. The discarded wax blocks piled up into a small mountain in the corner.

On the afternoon of the fourth day, the first batch of quartz sand shells that perfectly matched the drawings were finally sent into the high-temperature furnace.

As the dark red molten steel slowly poured into the pouring spout, the entire workshop was so quiet you couldn't even hear a breath. Several hours later, the temperature dropped. Master Li, holding a small iron hammer, squatted in front of the gray-black sand shell, his hand trembling twice before he dared not strike.

"Smash it," Lin Jiaoyue said calmly.

"Snap!"

The outer quartz sand shell shattered and peeled off.

In the dim light of the workshop, a stainless steel impeller with a deep blue metallic luster suddenly appeared before everyone's eyes! Its surface was as smooth as a mirror that had been polished countless times, and the curves of the six impeller blades were smooth and beautiful, exuding a captivating industrial aesthetic.

Lu Zheng rushed forward, pulled out the vernier caliper from his pocket, and wedged it against the edge, staring intently at the scale on it.

There was no sound.

A full half minute passed before he suddenly raised his head, his throat bobbing violently:

"Exactly perfect...not a single error!"

"Boom—" The entire workshop instantly erupted in chaos.

Master Li held the still-warm impeller, touching it over and over, his eyes suddenly reddening:

"Incredible...this method is incredible! I've spent my whole life tinkering with lumps of iron, and I never dreamed that you could make lumps of iron by playing with mud! If a whole row of furnaces were lit, we could produce over a hundred a day, outworking the German machine tools until they were broken!"

With the most challenging impeller secured, the subsequent work proceeded with ease. The pump body was directly cast from ordinary carbon steel from the converter, and the motor coils were so easy for the 909 Institute that they could wind them with their eyes closed.

In less than half a month, the first batch of fifty brand-new centrifugal water pumps were neatly stacked in the yard. The machines were painted a bright grass green, with the words "Dongfeng" (East Wind) sprayed in red on the outer casing, and a circle of wheat ears fluttering in the wind printed next to them.

Upon hearing the news, Director Zhang rushed over in his jeep without even having breakfast. After circling those green metal lumps three times, he didn't say a word and immediately dispatched four military trucks, carrying Lin Jiaoyue, Lu Zheng, and one of the water pumps, heading straight for the Hongxing State-owned Farm on the outskirts of Beijing.

……