88: Chapter 88 Tolerance Standards, Old Tom Looks at Her with New Eyes

The forging hammer fell. It wasn't a single sound, but a continuous string of dull thuds.

The piston of the steam forging hammer struck the steel billet at a frequency of forty times per minute, each blow making the workshop floor tremble.

Years of rust and coal dust fell from the rafters, dropping into the cooling pool and creating tiny ripples on the dark, murky surface.

Old Tom squatted by the pool, his knuckles white as he gripped a wrench—the drive belt had slipped by half a notch again.

He opened his mouth to curse, but the sound was crushed into nothingness by the roaring noise the moment it escaped his lips.

At the workshop entrance, Deputy Medical Officer Vian stood for a moment.

Her left hand was still pressed against her ribs; the bandages from the Medical Station were wrapped tight, yet every breath brought a dull, heavy friction from the fractured bone.

The doctor's orders said she should lie down for another week.

She lifted her leg and stepped over the threshold.

The forging hammer slammed down heavily once more. This time, Old Tom looked up.

"You've come to the wrong place." His voice was booming, not out of unfriendliness—having been soaked in the noise of the forging hammer for forty years, he had long forgotten how to speak softly. "The Medical Station is in the south of town, white building, with a red cross hanging at the door."

"I know where it is." Vian's voice wasn't loud, but every word clearly pierced through the roar. "I came to the Arsenal. Aunt Zhang said you were modifying the trigger springs for the tripwire fuses, increasing the precision by a notch. Your apprentices always deviate by a few tenths of a millimeter when reading the tolerance scales."

Old Tom took off his reading glasses. The lenses were covered in a layer of grayish-white metal powder; he wiped them casually with his thumb—making them even blurrier.

"You're a medical officer, coming to look at springs?"

"Lying down is just lying down." Vian's tone was flat, exactly the same as when she had said "I'll take the second half of the night"—she wasn't here to help, but to evaluate. She pulled a caliper from the inner layer of her medical kit. "I have this."

Old Tom's gaze was nailed to the caliper, and the wrench in his hand froze.

It wasn't standard issue from the Imperial Arsenal. Its streamlined alloy casing, fully sealed scale window, and the edges of the measuring jaws glinted with a cold blue light in the dim workshop. It had a precision of 0.01 millimeters—you probably couldn't find a third one in the entire Eastern Frontier Sector of the Empire.

"Where did you get this?" Old Tom's voice dropped half a tone. It wasn't suspicion, but the instinctive excitement of a man who had forged iron his whole life upon encountering a fine tool.

"From a crash wreckage, a standard calibration piece from the medical bay." Vian placed the caliper flat on her palm and held it out. "It's standard issue for the Astral Knights. When we were scavenging supplies by the swamp, I specifically tucked it into my innermost pocket."

Old Tom took the caliper. Those hands, which had stood before the anvil for half a century, were as steady as if holding his own forging hammer when they took this precision tool he had never seen before. He gently pushed the measuring jaw with his thumb, watching the needle in the scale window sweep smoothly across.

"0.01." He read it slowly. "The tolerance for these springs of mine, the Imperial Arsenal standard considers 0.1 to be acceptable. Your ruler is ten times finer than the standard."

"That's why I brought it."

Old Tom handed the caliper back. He didn't say "I don't need it," but instead asked another question.

"Do you know why my apprentices are always off by a few tenths?"

Vian shook her head.

"Because their hands haven't been burned enough." Old Tom spread out his right hand. The calluses on his palm weren't just one layer, but several stacked together, the oldest ones already worn down to a dark yellow. "I've forged iron my whole life; what kind of steel, at what temperature of water, and how many microns it will shrink—my hands know. My brain might not calculate it clearly, but my hands know. Those kids' hands are still tender; they can only rely on their eyes, and relying on eyes leads to deviation."

Vian looked at his palm and was silent for two seconds.

"My eyes won't deviate," she said. "But my hands don't understand iron like yours do. That's why I brought the caliper—your intuition tells me what should be measured, and my caliper tells you what the measurement actually is."

Old Tom didn't respond. He walked to the anvil, picked up a piece of spring blank that had just been quenched, and handed it to her.

"Measure this."

For half an afternoon, the two of them exchanged words by the cooling pool; the nearby apprentices stopped their work and gathered around to listen.

Vian's caliper clamped onto the first coil of the spring. Once the needle steadied, she called out the number: "Inner diameter 12.74, positive tolerance 0.02." She measured again from a different angle. "Outer diameter 14.21, negative tolerance 0.01—this one is qualified."

"Say that... tolerance thing again." Old Tom squatted beside her, clutching a piece of chalk.

"Positive 0.02 means it's 0.02 millimeters larger than the standard."

"Larger means it's looser."

"Correct."

"Then why not just say it's loose?" Old Tom squatted and drew a vertical line on the ground. "How much looser—0.02, I've noted it down. Larger than standard is called positive, smaller than standard is called negative, right?"

He wrote "Positive" on the left side of the vertical line and "Negative" on the right. The handwriting was crooked, but the proportions were perfectly divided.

"The Imperial Arsenal standard—" Vian just started.

"That standard is just a piece of paper in my workshop." Old Tom interrupted her. "Your 0.01 is what's real. The standard on paper is for the lords in the offices on Terra to see; the ruler in your hand is for me to see."

Vian looked down at the caliper, then raised her eyes to look at Old Tom.

"My caliper can turn intuition into numbers."

"My intuition can verify if the numbers are correct." Old Tom finished the second half of the sentence for her.

The two exchanged a glance. Among the apprentices watching the commotion, someone muttered, "Old Tom actually didn't curse."

"Shut up." Old Tom didn't even turn his head. "She's holding a caliper, you're holding your eyes. Eyes can deviate, calipers don't. When your hands are as burned as mine, then come tell me your eyes are enough."

He turned and pointed to the steam forging hammer running in the corner: "Can this ruler measure how much the steel billet is compressed when the hammer strikes?"

Vian looked at the forging hammer, then looked down at the caliper.

"Not in the instant it strikes. I can measure the compression ratio after it cools, but instantaneous measurement requires a pressure sensor. A medical caliper doesn't have that function—"

She suddenly paused.

Pressure sensors, high-speed photography... in this Arsenal cobbled together from steam and scrap, talking about these things was too far-fetched.

"—however, if we were to engrave a set of scales on the piston rod of the hammer—"

Old Tom raised an eyebrow. He didn't care about any "pressure sensors," he only heard "engrave scales on the piston rod."

"You mean adding a needle to the drive arm." He gestured along the side of the drive arm with his index finger, his fingertip slightly bent from years of holding a hammer. "The tip of the needle brushes across the surface of the steel billet; however far the hammer goes down, the needle moves that much. No need for any expensive machinery—" He patted his own thumb. "A needle, a piece of paper with markings is enough. When I was young and repairing steam engines on the railway, that's how we measured the deviation of the connecting rod stroke; back then, we didn't even have proper rulers."

Vian's gaze fell on his thumb—that callus soaked in rust and machine oil for decades.

"My caliper has a precision of 0.01 millimeters. What is the precision of your thumb?"

Old Tom was stunned for a moment, then laughed. The laughter was mostly swallowed by the roar of the forging hammer, but the wrinkles on his face all smoothed out.

"Lass, are you testing me? There are no markings on my thumb, but I can feel how much softer one spring is than another. You ask how many millimeters that is, I can't say, but I know it's not right."

"That is intuition."

"That is intuition." He repeated.

"Put them together," Vian said, "numbers verify intuition, intuition supplements numbers. Without adding new equipment, we can raise the precision of the Arsenal by an order of magnitude."

Old Tom didn't respond. He rummaged through his toolbox, pulled out a long, thin steel rod, inserted it into the newly machined gun barrel, and pushed it through with his eyes closed.

"When this bore gauge slides through—" He tapped a point in the middle of the gun barrel. "My hand can feel every uneven spot on the tube wall. Here, the wall is thinner. How much thinner I can't say, but it is just thinner."

Vian reached out and took the bore gauge, mimicking his movements, and pushed it through with her eyes closed. When she opened her eyes, her expression had changed—it wasn't the calmness of measurement, but the astonishment of a person who had undergone precision training suddenly encountering another kind of "instrument" they didn't know how to use.

"I didn't feel it."

"Your hands haven't been burned." Old Tom said. "In another twenty years, you'll be able to feel it."

Vian spread out her left hand. There were no calluses on her hands, but every fingertip was left with fine needle pricks—the marks left by holding medical suture needles.

"In another twenty years, your hands will be able to feel an error of 0.024 millimeters, and my hands will be able to suture blood vessels under one millimeter." She said softly, "We don't lack precision; what we lack is using the same language to bring these two kinds of precision together."

Old Tom chewed on these words for a few seconds.

"Fine. We'll do it your way. You report the numbers, I'll tell you the intuition. The places where they don't match—"

"The places where they don't match are the blind spots of each method." Vian continued, "Once we find the blind spots, the standard can be considered truly accurate."

At dinner, Old Tom and Locke sat at a table together. Locke slammed his ale bowl onto the table, the dull thud making the rim of the bowl wobble. Old Tom stirred his chopsticks in his bowl twice, picked up a slice of pickled radish, then put it back down.

"That white-haired woman," Old Tom began, "is the same kind of person as Lin Mo."

Locke looked up: "What kind?"

Old Tom thought for a moment, tapping the tip of his chopsticks against the rim of the bowl twice, two crisp sounds, as if calibrating something.

"They both ask 'how much more is missing,' instead of asking 'why is there such a big difference.'"

Locke didn't quite understand; he picked up his ale bowl and brought it to his lips, then paused.

"The last time you spoke about Lord Lin Mo like that was when he was asking about iron ore inventory at the Town Hall."

"Right. You drank up all the ale before I had finished."

Locke was silent for a moment, then tilted his head back and downed the remaining half bowl of ale in one gulp.

"Is she coming again tomorrow?"

"She said she would. Her ribs haven't fully healed yet."

"Running over here when she's still injured?"

"She said lying down is just lying down anyway."

Locke set the empty bowl on the table, the clatter of the bowl's bottom against the wood much softer than before.

"She's got the same foul temper as you."

Yang Shitou leaned over from the next table, holding a bowl of thin porridge.

"Uncle Tom, I heard she checked that entire batch of tripwire springs with a caliper?" Yang Shitou's voice was, as always, soft. "That antenna at the relay station was off by a fraction of a degree again today; I spent an hour adjusting it. When it comes to precision, being off by just a little bit means being off by a lot."

"Checked them all." Old Tom popped a pickled radish into his mouth this time. "She picked out four of them, put tape on each one, and wrote numbers on them."

"Four?" Yang Shitou set down his porridge bowl. "Didn't you never pick them out before? You always said if it felt right in your hands, it was good enough."

"That was then." Old Tom swallowed the radish. "From now on, it's not just about the feel. She calls it tolerance, and I'm adding another check for that tolerance."

Wang Defu, sitting in the corner, hadn't said a word, holding his dry pipe, the ember on the tip glowing on and off in the dim canteen. He had managed the Blackstone Town granary for three years and had dealt with numbers his whole life, yet he was always quieter than the others.

"Tolerance, huh..." He took the pipe from his lips. "It's the same principle as grain storage. You say a bag of wheat is eighty pounds, the person weighing it doesn't care if you're off by half a pound; if it's less, it's less. It's the same with making springs. Old Tom, you used to make them based on your conscience, but now someone has brought a ruler and measured your conscience for you."

Old Tom glanced at him. Wang Defu put the pipe back in his mouth, the smoke drifting slowly from his nostrils.

"You manage grain, I manage iron," Old Tom said. "But you're right—numbers don't lie."

"Numbers don't lie." Wang Defu stood up and brushed the ash off his pant legs. "But numbers don't just appear on their own; someone has to measure them. That white-haired girl is willing to go to this much trouble, and that's worth more than anything."

After the night shift at the Arsenal began, Vian still hadn't left.

She used a caliper to check the tolerance of every single trigger spring for the new-style tripwire mines. The springs passed through her fingers one by one; the qualified ones were tossed into the finished-product box, while the unqualified ones were stacked separately to the side. Her fingertip was sliced by a tiny cut from the edge of a spring—not really a workplace injury, just her being too focused on the reading and not noticing her fingertip pressing against the sharp edge of the steel. A bead of blood seeped out; she pressed it against a bandage and continued measuring.

Old Tom saw the cut and rummaged through his toolbox, pulling out a roll of bandage made from old military uniform strips and handed it to her.

"My wife used to be the same way when she cut her hand slicing apples—didn't make a sound."

She wrapped the bandage and continued measuring with her head down.

When she reached the third batch of springs, she stopped. The caliper needle was off—off by less than 0.03 millimeters. She took that spring out separately and measured it again. Sure enough, the tolerance was exceeded.

She measured the next one, then the next. Four in total.

The tolerance of the four springs exceeded the range she had set. The difference was only a few hundredths of a millimeter, but she had written clearly in her training materials from the Astral Knights: such tiny dimensional deviations would be magnified by the slight metal expansion during humid, rainy weather, eventually leading to excessive delay in the tripwire mine's trigger.

"These four won't do." She placed the springs on Old Tom's toolbox, tore off a piece of tape, and wrote a few lines on it—the tolerance values, the deviation range, and four words: Re-quench.

Old Tom walked over, looked down at the four springs, and then at the words on the tape.

"According to Imperial Arsenal rules, this slight difference counts as qualified, counting towards the batch's pass rate."

"Blackstone Town doesn't have batch pass rates." Vian didn't look up, the caliper already gripping the next spring. "Every single tripwire mine here only gets one chance. If it fails to trigger once, that Chaos Scout will step right over it and sneak into the Arsenal's side door."

Old Tom was silent. He picked up the four springs, weighing each one in his palm, his thumb rubbing along the arc of the spring—feeling the subtle difference that only a blacksmith of fifty years could discern.

"You're right." He peeled the tape off the toolbox and tucked it into the production log, which was frayed and soaked in oil. "I checked these by feel, and I thought they were fine. The caliper says they aren't, and this time, the caliper is right."

He picked up a file and sat back down by the cooling pool. The forging hammer roared incessantly in the night shift workshop; sparks flew from the spring blanks under his hands, landing in the water pool with a hissing quenching sound. He reground the four springs, each one ground down to the narrowest column in the tolerance table Vian had provided.

After finishing, he stood up and stretched, his lower back emitting a series of crisp cracks.

"Next time you come," he said to Vian, who was counting the finished product box, "let me see that evaluation form you gave Lin Mo."

Vian's hand paused for a moment on the finished product box.

"Although I haven't read many books," Old Tom blew the iron filings off his file, "I can tell what's good and what's bad. I've been smithing for half a century, and your inspection standards are correct."

The workshop was silent for a moment, with only the water in the cooling pool bubbling.

Vian didn't respond.

But the next morning, Old Tom found a stack of papers on the cover of his production log—it was a transcript of the Medical Station section from Vian's evaluation report, attached with instructions on how to handle tolerance anomalies. The handwriting was too neat to have been written in the workshop, and there was no signature.

Old Tom turned to the last page and drew a circle in the blank space with a charcoal pencil.

The meaning of the circle was: from now on, this page was the official rule for his toolbox.

Vian stayed in the Arsenal until late at night. She had finished measuring all the springs for the new-style tripwire mine fuses—a total of two hundred and sixteen, with two hundred and ten qualified and six requiring rework. All the reworked springs had undergone secondary quenching and grinding by Old Tom's cooling pool, with every single one passing both the caliper and the feel tests.

She had three bandages wrapped around her fingers. It wasn't that she had been injured three times, but the same cut had split open twice while repeatedly pressing down on the springs. Each time it split, she re-wrapped it with a bandage and continued measuring with her head down.

Outside the window, torches were moving along the walls of Blackstone Town; Locke's night patrol was changing shifts. From the direction of Yang Shitou's communication relay station came a very short calibration pulse—he was still adjusting that antenna which had been knocked out of alignment by a stray bullet. In the night, the entire Blackstone Town was running non-stop in unseen corners.

A tolerance of 0.01 millimeters, on a medical caliper salvaged from a plane crash wreckage, and on the thumb of a blacksmith who had been smithing for half a century, was measuring the same thing, using two different languages. But the moment they intersected in the corner of the Blackstone Town Arsenal, no one felt that these two languages needed translation.

The mirror of the emperor flickered very lightly at the edge of the vision—not a warning, but a confirmation.

A line of golden text then spread across the edge of the vision, not an analysis, nor a hint, but a poem. The emperor had placed an ancient style poem from the home planet Earth between two people who were pursuing the same standard in different ways:

"Minute precision discerned on the scale, fifty years of iron-working hands remain."

"Numbers silent, the heart knows true, in forging's depths, two souls commune."

The golden text lingered at the corner of the eye for a moment, then, like sparks splashed up by a forging hammer, dissipated one by one on the surface of the cooling pool water. Old Tom didn't see these words, but the spring in his hand, at that very moment, was ground down to the narrowest column of the tolerance table. Vian didn't see them either, but the caliper needle at her fingertips, at the same instant, stopped steadily at the 0.01-millimeter mark. Two languages intersected under the golden gaze of the emperor—no translation needed, because precision itself was the only universal language.

And in the deeper night sky, outside the thin atmosphere of Hope Star, a dark red trail that did not belong to any Imperial satellite was slowly streaking across.

No one could see it with the naked eye, and no radar could capture it. It was an atmospheric probe of the Chaos patrol fleet—a monitor forged from Khorne brass and Tzeentch crystals, no bigger than a human fingernail, its shell covered in Warp runes. Every time it orbited, it recorded Hope Star's surface thermal distribution, population density, and defensive fortification locations into an Obsidian core the size of a fava bean.

Three months later, this probe would complete its orbital decay and fall into the atmosphere of Hope Star. Before it burned up completely, it would send all the data back to the Chaos patrol fleet in the form of a Warp pulse.

By then, Chaos would know the exact coordinates of Hope Star.

Before it arrived, Blackstone Town still needed many, many tripwire mines. Every single spring only had one chance.

The mirror of the emperor flickered again at the edge of the vision—a very faint golden halo, like a person who had sat in darkness for ten thousand years, gently nodding.