Chapter 2438: Sonia (XV)

"4,900 meters!" After working for a while, the petty officer operating the rangefinder finally reported a number. Li Di secretly shook his head—the accurate figure should be just over 5,000 meters; he had just measured it with a laser rangefinder. But the number was close enough. After the cannon fired, one could see where the shell landed and make slight corrections—not a problem. Though admittedly they were currently on a floating dock with minimal rocking, and the sea was calm. Out at sea, the error would probably multiply several times over. He watched Lin Hanlong direct his people to set up a small canopy right over the rangefinder.

"What, is this thing afraid of water or sunlight?"

"Both. Also afraid of humidity and salt spray."

"Such a delicate thing."

"You want the good stuff but fear it being delicate?" Lin Hanlong laughed. "I haven't even required a vacuum and dust-free environment yet..."

"No, no—our navy doesn't need such fancy equipment," Li Di said. Currently, the optical factory's telescope production was normally stored in moisture-proof boxes with lime that was regularly replaced to absorb moisture. Even so, problems like mold and salt accumulation still occurred, requiring regular gentle wiping with special lens cloths. Every so often, large batches had to be returned to the factory for maintenance. This large device seemed to have no sealing measures—what would happen when it got moldy and rusty?

"If it weren't that we brought so few one-meter rangefinders from the old timeline, I wouldn't even want these things..."

"Relying on old-timeline reserves—how long can that last? Besides, the quantity isn't enough for your navy's equipment plans." Lin Hanlong said. "This is an experimental product; I haven't even added sealing—makes it easier to open. After all, it needs frequent adjustments. When it's actually installed on ships, it'll naturally be fully sealed."

"How's the sealing effect?"

"For that, we have to thank Old Huang. Despite some people in the Senate cursing him daily as a traitor, he's gotten us quite a few good things—like chamois leather and fir wood. I estimate the finished product's trouble-free usage period can probably be maintained for three to six months."

Treated high-quality deerskin made acceptable sealing components. Sap extracted from fir wood, after refining, though slightly yellowish, could still be used as optical cement. Lin Hanlong also planned to design several desiccant containers in the rangefinder to ensure internal dryness. He estimated that with effort, this rangefinder could last three to five months at sea without problems, then return to the factory for maintenance. He considered this acceptable for an experimental product. In the future, the Navy would certainly need dedicated personnel and equipment for optical maintenance. He just needed to train these people properly.

"When do you think we can organize finalization?" Li Di felt the performance was marginally acceptable. A three-to-six-month cycle was also sufficient—after all, naval warships couldn't continuously deploy at sea for too long either.

"Anytime. Performance is as good as it can get with what we have." Lin Hanlong spread his hands.

"Alright, I'll arrange it as soon as possible," Li Di said. "As for the model designation, I think we'll call it Trial Type 1 Two-Meter Naval Rangefinder. After finalization, we just drop the 'Trial.'"

By the time Lin Hanlong returned from Maniao to Bairen, evening had already fallen. As soon as he reached the optical factory, Cai Junjie reminded him: he'd been away for several days—better hurry home.

"What's the rush?" Lin Hanlong was very attentive to the optical factory he had built from scratch. No matter how late he returned from being away, he always walked around the factory first, checking if production was normal and whether workers were following procedures. "The house will still be there whether I go back early or late."

Cai Junjie was speechless. He could only look to his father—Cai Shengjie, currently responsible for managing the factory's daily affairs. He had a pair of reading glasses with a cord perched on his nose.

He first reported that a Senator from the Nanyang Company had come looking for him, saying he had important matters to discuss. Lin Hanlong gave an indifferent grunt. Too many Senators came looking for him. Everyone had important matters. In the end, they all just wanted to "pull strings" for some optical instrument or other.

"No rush. If he has urgent business, he'll naturally come again," Lin Hanlong said. "How's the trial production going on the new equipment?"

The factory had recently received several new grinding machines—equipment manufactured in Lingao often had very short lifespans. First, early-stage components were mostly of low quality with poor assembly precision. Second, upgrades were rapid. Whenever industrial departments made certain advances, new equipment would often see qualitative improvements, making old equipment quickly obsolete. Take his optical factory's equipment—almost every year a batch had to be replaced with new ones.

Cai Shengjie took out the process record book and handed over a wooden box.

"These are the lenses trial-ground with the new equipment."

Lin Hanlong picked up the glass lens, turned on the work light, and examined it briefly. His brow suddenly furrowed.

He busied himself at the workbench for a while, then looked up. "Old Cai, call the General Machinery Factory for me. Ask if Yuan Haowen is still there."

"Chief, it's already dark, and you just got back. Can't this wait until tomorrow?" Cai Shengjie advised.

"Just make the call. Yuan Haowen is definitely still at the General Machinery Factory right now."

"This equipment you made has too much gap tolerance!" Lin Hanlong took out two just-ground lenses and placed them on Yuan Haowen's desk. "Look for yourself at the lenses ground with your equipment."

As he spoke, Lin Hanlong folded his arms before his chest, watching Yuan Haowen with amusement. Yuan Haowen casually turned on the work light, pulled out a sheet of white paper to spread on the workbench, put on gloves, and slowly placed one lens on the paper. Then he stacked the other lens on top—and saw colored fringes appear. These were Newton's rings produced by equal-thickness interference effect.

However, these Newton's rings really didn't resemble circular rings—some were elliptical, some egg-shaped, some areas had many fringes crowded together. In any case, they couldn't be called circular rings.

"Old Lin, looking at this fringe density and range, this spherical surface's radius should be close to a hundred meters," Yuan Haowen said unhurriedly. "This is already the grinding machine's processing limit. What are you grinding such lenses for?"

Lin Hanlong was startled. He had ground these two lenses just to test the newly received grinding machine's precision, without thinking of any practical use. He hadn't expected Yuan Haowen from the mechanical sector to see through it. "I was just testing precision—hadn't thought of practical uses yet. Though historically, before achromatic technology matured, there were lenses with focal lengths of dozens of meters..."

"But that wouldn't need nearly hundred-meter spherical radii!" Before Lin Hanlong finished, Yuan Haowen interrupted. "But our mechanical sector really does need such large-radius curved surface equipment. If it weren't for seeing you busy every day with rangefinders and telescopes and artillery scopes for the navy and army, I would have submitted a report to the Executive Committee long ago."

Yuan Haowen stood up and put his arm around Lin Hanlong's shoulder. "The old-timeline machinist's box-type spirit levels had a graduation value of 0.02mm/1m. Back then the mechanical sector didn't have a proper machinist—we only brought a dozen or so sets of this equipment. Now which unit doesn't need them? I only have two here. Usually, I only dare use one—won't even let naturalized citizens touch them."

He fished out keys and opened a cabinet beside the marble surface plate, taking out a large wooden box. On it was written "Box-Type Spirit Level" in large characters, with a line of small print: "Shanghai Measuring Tools and Cutting Tools Factory."

Yuan Haowen opened the box and took out a metal frame about 30 centimeters square, standing it on the marble surface plate. "This is it."

Lin Hanlong examined it carefully. The metal square frame was about 5 centimeters wide, straight on all four sides with special patterns. The bottom and left side flat surfaces had V-shaped grooves about three centimeters wide, presumably for convenient measurement of cylinders. Inside the frame's bottom were set one large and one small spirit level, with bubbles inside. The large spirit level was parallel to the frame; the small spirit tube was perpendicular to the frame. One side also bore Shanghai Measuring Tools and Cutting Tools Factory's insignia and the marking "20μm/m." At this moment, the bubble in the main spirit level was steadily positioned in the center.

"The main spirit level's graduation intervals are about two millimeters—the corresponding arc radius is exactly one hundred meters." Yuan Haowen spoke slowly from behind Lin Hanlong as he watched him examine it.

"No wonder you immediately agreed to set the grinding machine's limit at 100 meters!" Lin Hanlong suddenly understood. "I never imagined—one of us in optics, one in mechanics—how did we end up thinking alike? Just for your own mechanical sector's sake, you need to find ways to improve the grinding machine's precision!" He laughed as he spoke.

"Easy for you to say—this is a major project!" Yuan Haowen produced two bottles of kvass from somewhere, handed one to Lin Hanlong, then took a swig himself and said slowly: "I could guess this optical equipment would have problems. Because precision is expensive."

Yuan Haowen slowly opened up the topic. "Everyone knows the core of standardization is precision control and management. But what does precision rely on for realization?"

"On testing!" Lin Hanlong had just taken a sip of kvass and was in good spirits from the earlier conversation, so he boldly interjected.

"Right, on testing—or rather, guaranteed through measurement." Yuan Haowen paused. "What does measurement depend on?"

"Measuring tools!" Lin Hanlong said decisively.

"Right, the problem is with the measuring tools!" Yuan Haowen thumped the kvass bottle on the desk and launched into a lengthy discourse:

"Parts precision is guaranteed by tool processing and gauge measurement. But who guarantees the gauges' precision? That's metrology work. For example, in old-timeline factories, every vernier caliper was verified by the Metrology Bureau every six months. If precision wasn't up to standard, it had to be repaired or scrapped—though later you'd just buy new ones. Not just vernier calipers—balances, weights, thermometers, voltmeters, stopwatches—which of these isn't a measuring instrument? We've been so busy since D-Day that we've never gotten around to this. Plus with such overloaded use, I estimate half our measuring tools need repair or even scrapping. That's precisely why design precision can't be guaranteed, which is what caused your batch of equipment to have problems." Yuan Haowen took a sip of kvass and continued.

(End of Chapter)