The warmth of the family dinner hadn't even faded when Liu Li became even more diligent at work—she's now a first-class worker and the head of the QC team. With Master Wang supervising her and teaching her new skills, she dared not be careless in the slightest.

Every day, she would arrive at the workshop early as usual, wiping down the machine tools and checking the cutting tools. When working, she only had eyes for the parts and dimensions, not even caring about the calluses on her hands that hurt. During breaks, she would take a small notebook and chat with Zhang Shulan and Li Weidong about the QC team. Fu Jingchen would also often come over, bringing some data reports or materials copied from the library. The group would gather around the toolbox, discussing how to reduce the scrap rate.

Master Wang began teaching her how to adjust the newly arrived universal milling machine. This machine was much more complex than a lathe, with gears and drive shafts forming a maze. Liu Li listened very attentively, mentally reviewing each sentence her master spoke, and even responding with her own thoughts: "Master, shouldn't the guide rail clearance be adjusted to match the speed?" Master Wang didn't smile, but his eyes lit up, and he nodded: "Your mind isn't blank, not bad."

Fu Jingchen came to the workshop more often, sometimes to deliver blueprints, sometimes just to stand by the milling machine for a while, waiting for Liu Li to stop working. He would hand her a bottle of cool water and chat for a bit, saying things like, "The indexing mechanism on this milling machine is a little different from what's in the book," or "There's a new cutting fluid formula from abroad; maybe we could try it." They mostly talked about technology, and occasionally when they bumped into each other in the canteen, they'd chat about what was happening at the factory. That unspoken understanding, that grasped things in just a few words, slowly built up—quietly, but very genuinely.

The atmosphere in the workshop has also changed. Before, some people whispered behind Liu Li's back that "women can't do technical work." Now that they see that she can really solve problems, when they encounter something they're unsure about, they will take the initiative to ask, "Liu Li, how can you measure this size more accurately?" Liu Li never holds back and speaks her mind. Over time, everyone respects her.

Life went on smoothly like this. Liu Li even thought that once she learned how to use the milling machine, she would move forward with the second project of the QC group. Unexpectedly, trouble came knocking on her door beneath the calm surface.

That afternoon, the air was particularly stuffy, and even the sounds of the machines in the workshop had a sticky, humid quality. Liu Li was adjusting the milling machine guide rails with Master Wang when suddenly her ears perked up—there was a different kind of buzzing sound, as faint as a mosquito's chirp, mixed in with the machine noise, sometimes there and sometimes not.

"Master, do you hear that? Something sounds off." She stopped using the wrench and pointed into the workshop. There were several valuable pieces of equipment there, one of which was a precision gantry grinder imported from East Germany, used to process key parts for military orders. It was the factory's "precious treasure," and no one dared to touch it casually.

Master Wang listened intently for a while, then his face darkened: "It's that grinding machine."

No sooner had he finished speaking than Master Dong, the operator of the grinding machine, rushed over, his face pale. He went straight to Director Zhao and said, "Director Zhao! Something's wrong! The grinding machine is malfunctioning! The precision of the work being processed is out of tolerance, and it's full of vibration marks! I checked the grinding wheel and the spindle, but I couldn't find anything wrong. However, when I put my hand on the machine bed, I can feel a slight vibration!"

Director Zhao panicked as soon as he heard this—the grinding machine was working on a military order, and the tolerances had to be down to the micrometer level; even a slight deviation was unacceptable. He quickly walked toward the grinding machine, with Master Dong following behind, his voice trembling: "It wasn't obvious when we first discovered it, but it got worse and worse, so I quickly stopped the machine to prevent producing even more defective products."

The news spread quickly, and the noise from the machines in the workshop gradually subsided. The workers stopped what they were doing and looked towards the grinding machine. Master Wang and several veteran workers also gathered around, and Liu Li followed, but didn't dare to get too close, standing on the side to watch.

Director Zhao squatted down next to the grinder and tapped the machine bed with his fingers: "Try starting it up again, run it under no-load."

Master Dong carefully pressed the start button, and the faint "buzzing" sound rang out again, accompanied by a slight vibration. You could feel the regular vibration when you put your hand on it.

"Are the drive gears misaligned?"

"Is the spindle bearing lacking oil? These imported bearings are very delicate."

"Have you checked the hydraulic system? Unstable pressure can also cause shaking."

The veteran workers chatted amongst themselves, but none of them dared to touch it—the grinding machine was too complex, and most of the blueprints were in foreign languages. They didn't even dare to disassemble the outer casing casually, because if they damaged a key component and delayed a military order, no one could bear that responsibility.

Director Zhao frowned deeply, squatting there without saying a word. Calling in experts from the bureau would take several days, delaying the order; repairing it himself was out of the question—no one dared to make the decision.

Liu Li stood to the side, her eyes never leaving the grinding machine, pondering: This vibration doesn't seem like a completely broken part, but rather like a rotating component is misaligned, causing it to vibrate at high speed, and the vibration eventually leads to a decrease in precision. But this was just a guess; without evidence, she dared not speak rashly.

Master Wang circled the grinder twice, not touching it, just looking at it with his eyes, and finally sighed: "This foreign thing has too many tricks up its sleeve. You can't touch it without being absolutely sure."

The atmosphere in the workshop suddenly became heavy, and even the machines fell silent. Liu Li knew that if the grinder stopped, things would get much worse, and the previous peace would likely be shattered. She gripped the wrench in her hand, wondering if she could find some more clues, but looking at the enormous machine, she felt uncertain—this hurdle was much harder than the previous skills competition.