On the day the first ball joint was completed, Liu Li was not complacent—completing a single part is nothing; to get the workshop to actually use this device, we need solid data to speak for itself.

“We need to do comparative testing.” The next morning, when Fu Jingchen came to the workshop to check on the progress, Liu Li told him, “Use the old method and the new equipment to machine a batch of parts each, and compare the time, the pass rate, and the smoothness of the surface.”

Fu Jingchen's eyes lit up: "That's a great idea! I'll go draw up a record sheet right now and list out the dimensions, time, and test results clearly."

The test was scheduled for the afternoon. As soon as the news spread, a large crowd gathered in the workshop, including Director Zhao, who stood next to Master Wang with a small notebook in his hand.

Liu Li first demonstrated the old method. Holding the two feed handles with both hands, her eyes fixed on the workpiece, she relied entirely on her feel to "find" the curvature of the sphere. Soon, sweat dripped from her forehead; even a slight tremor of her hand would leave marks on the workpiece surface. It took her a full eight minutes to machine one ball end. When she checked it against a template, the dimensions were just right, and the tool marks were still visible on the surface.

"Let's look at the new device." Liu Li wiped her sweat and installed a different part.

This time, she only moved one vertical handle, and the device itself guided the blade tip along an arc. With a few "swish" sounds, in less than three minutes, a ball head came off. Measuring it with a micrometer, the size was right in the middle of the tolerance, and the surface was so smooth that you could see your reflection in it.

People around him exclaimed "Oh!" and Director Zhao picked up two workpieces to examine them, nodding repeatedly.

Liu Li didn't stop, completing ten in one go. Fu Jingchen was recording the data beside her. After writing down the last number, he looked up: "An average of three minutes and fifteen seconds per car, all ten passed! More than twice as fast as the old method!"

Master Wang, who had been silent until now, suddenly spoke up: "Try different sizes."

That hit the nail on the head. Liu Li quickly replaced the workpiece with one of smaller diameters, adjusted only the two positioning screws on the device, and soon machined a small ball head with the same precise dimensions.

"Great! This device can be widely adopted!" Director Zhao finally clapped his hands.

"Only ten vehicles and you're already praising it?" A sarcastic voice suddenly emerged from the crowd. Sun Peng squeezed to the front, arms crossed, "They might break down in two days. Who's responsible for the production delays then?"

Before Fu Jingchen could retort, Liu Li spoke first: "Master Sun is right, we really need to try again." She turned to Director Zhao, "Director, I want to use this device for the next batch of two hundred small connecting rods. Only if it can stabilize production can we truly say it's working."

The moment he said that, everyone fell silent—using an unfinished device for formal work was quite risky.

Master Wang nodded first: "Okay. This batch of work will be handled by Liu Li, and she will oversee the whole process."

Director Zhao hesitated for a moment, then nodded: "Okay, let's do it the way Old Wang said."

For the next three days, Liu Li worked tirelessly on the equipment. Every morning, she would check all the screws and connecting rods, even measuring the clearance of the slider with a feeler gauge. While working, she would keep half her eyes on the workpiece and half on the operation of the equipment, drawing countless operation record sheets. Fu Jingchen came every day to help her calculate data and sometimes even helped her change the cutting tools.

"We've reached one hundred!" On the afternoon of the third day, Fu Jingchen flipped through the record sheet, his voice trembling slightly. "Aside from the normal tool changes, the equipment didn't malfunction at all. The pass rate is over ninety-eight!"

Once this number was revealed, even the experienced craftsmen who had previously been critical had nothing to say.

On the fourth day, Liu Li was driving the last batch when the device suddenly made a "click" sound. She immediately stopped the car, lifted the protective cover, and saw that a guide slider had been worn into a small dent.

"What did I tell you!" Sun Peng immediately shouted, "This thing is just for show, it won't last long!"

Liu Li remained calm, picked up the slider and examined it: "This is normal wear and tear; all parts need to be replaced after a while. This slider has spun three hundred parts; it should have been replaced a long time ago." She opened her toolbox and took out a new slider—one she had prepared beforehand. In less than ten minutes, the new slider was in place, and the machine started humming again.

Even Director Zhao was impressed: "They even thought of spare parts. They've really thought of everything."

That evening, Liu Li and Fu Jingchen were organizing data in the office. Fu Jingchen pointed to the numbers on the report, becoming increasingly excited as he spoke: "Efficiency has increased by 140%, the pass rate has risen from 85% to 98%, and each part saves 5 minutes and 45 seconds. Based on the workshop's monthly output, that's a significant saving in man-hours!"

Looking at the streetlights outside the window, Liu Li said softly, "Now, no one should say this is 'not doing one's proper job,' right?"