The workshop was brightly lit in the early morning, even busier than during the day. The C620 lathe was disassembled into pieces, with parts laid out in a row on tar paper. The new bearings were placed in a blue cardboard box, gleaming coldly—this was the final "operation" step; whether the lathe could be turned around again depended entirely on this step.

“Xiao Liu,” Master Wang said, his voice as deep as the machine tool base, clutching a copper rod in his hand, “bearings are the bones of a machine. If they’re installed even slightly crooked, they’ll either make noise or not last long, and in severe cases, they can even damage the spindle. This step can’t be rushed; it has to be done steadily.”

"I know, Master." Liu Li took a deep breath, her palms were a little sweaty, but she wasn't flustered at all. She knew that what she held in her hands now was not just parts, but also the workshop's export orders and the trust her master had placed in her these past few days.

Reassembly begins with cleaning. Liu Li took a new silk cloth, dipped it in gasoline, and wiped the spindle journal and bearing housing holes again and again. She even used a fine wire to hook out the iron filings in the screw holes—not a single impurity could be left, otherwise the precision would be completely ruined.

Next, she installed the new bearing. Following the procedure, she placed the bearing in heated machine oil and waited for the inner ring to expand. With the help of Master Wang and the mechanic, she slowly used a puller to slide it onto the spindle. "Align it with the shoulder, be slow." Master Wang watched from the side, and Liu Li adjusted the angle by feel until the bearing clicked into place. Only then did she breathe a sigh of relief, sweat dripping from her forehead to her chin.

But the hardest part is yet to come—adjusting the spindle precision. The spindle box must be reinstalled on the machine bed, and then the radial runout and axial runout must be adjusted, both within three to five micrometers (one micrometer is 0.01 millimeters). Even a slight deviation is unacceptable.

The crane hoisted the heavy spindle box, and several people shouted in unison as it was slowly lowered and aligned with the bolt holes on the machine bed. Fu Jingchen had already set up the dial indicator, and Liu Li went over and gently placed the indicator needle against the spindle.

She manually turned the spindle, her eyes fixed on the dial indicator pointer. The first measurement showed a radial runout of eight micrometers, which was excessive. "The left side is too high; reduce the lower left corner shim by two micrometers," Liu Li quickly determined.

Master Wang didn't speak, but took a set of copper washers, measured them with a micrometer, and picked out a thin one to hand over. Replacing the washer required loosening the bolts and prying open the gaps. Several people worked for a long time, tightened them again, and measured once more. The pointer was at six micrometers. "Not good enough, add another micrometer to the upper right corner." Liu Li bent down to look again, her tone certain.

They kept adjusting things – measuring data, changing gaskets, tightening bolts. The workshop was so quiet that you could only hear the "squeak" of wrenches tightening screws and Liu Li occasionally reporting data.

"Radial runout, four threads."

"Axial movement, three and a half strands."

The onlookers held their breath. Zhang Shulan clutched her clothes, not daring to blink. Those who had previously said Liu Li was no good were now silent—this girl's patience and accuracy in adjusting precision surpassed even some veteran mechanics. Sun Peng, hiding in the back, turned pale and then green; his little tricks were utterly insignificant in the face of true skill.

As dawn broke, Liu Li had adjusted the dial indicator countless times. On the final turn of the spindle, the pointer hovered only slightly above or below zero, barely moving. "Radial runout, one and a half tenths of a second!" she said, her voice trembling slightly but steady. Fu Jingchen glanced at the other dial and added, "Axial runout, one tenth of a second!"

One and a half strands! One strand! Even higher than the factory standard!

"Good!" Master Wang finally shouted, patting Liu Li on the shoulder with his big hand, a rare smile appearing on his face. "Girl, this skill is good enough!"

The workshop erupted in cheers and applause. Zhang Shulan rushed over and hugged Liu Li, exclaiming, "Lili, you're amazing! The lathe is saved!" The experienced workers nodded in agreement, "Old Wang, your apprentice is even more talented than you!"

Liu Li smiled, her back aching from exhaustion, yet she felt completely relaxed. Director Zhao excitedly shouted, "Power on! Test drive!"

She switched on the power and pressed the start button. The motor hummed and started turning, the spindle following suit, without any unusual noise or wobbling. Liu Li placed her hand next to the bearing cover; it was only at a normal temperature, not hot. She took a blank part, secured it to the chuck, started the lathe, and as the cutting edge made its way down, shiny iron filings rolled out. The finished part was so smooth it was almost reflective, and when measured with a micrometer, the dimensions were perfectly accurate!

The roar of the machines echoed through the workshop, like a song. Liu Li stood in front of the lathe, a slight vibration at her feet, but a sense of accomplishment filled her heart—she had not only repaired the machine, but had also truly established herself in this workshop through her skills. Daylight had broken, and the sun shone through the window. She knew that the road ahead would be much smoother.