N-M Chapter 85 Ruler
Chapter 85 Ruler
Ding Haifeng squatted in the innermost corner of the used parts warehouse for almost a whole morning.
He picked out an old bearing housing from the shelf, then rummaged through his toolbox for a micrometer. He squatted down under the window, secured the bearing housing to the edge of the workbench, and began to measure it in the light filtering through the window paper.
Yesterday, Lao Fang said that refurbishing the water pump requires refitting the bearing clearance, but the service station doesn't have new bearings, so they have to pick the one with the least wear from the old parts.
The wear should not exceed three millimeters. If it exceeds three millimeters, the bearing will burn when the water temperature is high.
He clipped the micrometer onto the inner ring of the bearing and tightened the fine-tuning screw until the two clips of the micrometer gently gripped the inner ring wall.
The bite of the clip feels very light, as light as touching the surface of water with a fingernail.
He squinted at the scale.
The main scale has passed the 18 mark, and the fourth division on the vernier scale is aligned, indicating 18.04 millimeters.
He wrote the numbers down on a piece of scrap paper, rotated the bearing, and measured it again.
This time, the third division on the vernier is aligned, 18.03 millimeters.
He wrote it down, circled the two numbers together, and wrote "ellipticity, 0.01" next to them.
"That's not how you hold a micrometer."
Old Fang's voice came from behind.
Ding Haifeng turned around and saw Lao Fang standing by the old parts shelf with a cigarette in his mouth and a piece of copper pipe that had just been replaced in his hand. He didn't know when Lao Fang had come in.
"Your fingers are too close to the micrometer. Your body heat causes the scale to swell, making the measurements inaccurate." Old Fang put the copper tube on the shelf, walked over, took the micrometer from his hand, and took the cigarette from his mouth with his other hand. "Hold it on the heat-resistant pad, and don't let your fingers touch the scale."
Ding Haifeng looked at Lao Fang's hand.
Old Fang's fingers were thick, his knuckles were bulging, and there were oil stains that couldn't be washed off under his fingernails.
He held the micrometer on the heat-insulating mat, with his fingers about half an inch away from the ruler.
"understood."
"Measure one for me to see."
Ding Haifeng took the micrometer and remounted it on the inner ring of the bearing.
He imitated Lao Fang's gesture, pinching his fingers on the heat-insulating pad and suspending them in the air so that his fingertips did not touch the ruler.
When he was tightening the fine-tuning screw, he tightened it slowly, and stopped when the clasp gripped the inner ring, and did not tighten it any further.
Old Fang stood by and watched for a while, then put the cigarette back in his mouth and asked, "Where did you get that micrometer in your hand?"
"From the old parts warehouse toolbox."
"Do you know whose micrometer that is?" Old Fang's voice wasn't loud, but his tone had changed; it wasn't a question, but a test.
Ding Haifeng looked down at the micrometer handle.
Most of the black paint on the handle has been worn away, revealing a small patch of the original steel color, with a very shallow scratch on the side.
He turned the micrometer over and saw two crooked characters at the bottom of the handle, engraved with a steel needle: the character "海" (sea).
"Ah Hai's."
"When Ahai first arrived, Lao Qiu gave him this micrometer." Lao Fang leaned against the shelf of old parts, and the gears on the shelf wobbled slightly when his shoulder bumped against them. "Lao Qiu said that measuring tools are the eyes of a craftsman, and the eyes cannot be unreliable. Ahai practiced with this micrometer for three months, until he could tighten the fine adjustment screws without touching the body of the scale, and only then did he take it out to use."
Ding Haifeng looked down at the micrometer in his hand.
The character "海" (sea) is not carved deeply, and the strokes are crooked, but each stroke is made with enough force, as if it was carved by pressing down with a carving knife several times.
"Use this micrometer and practice according to Ah Hai's standards." Old Fang flicked away his cigarette ash, which fell onto the dirt floor of the old parts warehouse and piled up in a small clump. "The service station rules are that whoever uses the measuring tool must clean it and put it back in its place. Don't rush to put it back after you're done. Practice for a whole morning and measure all the data you just measured."
"I just tested them all." Ding Haifeng handed the draft paper to Lao Fang.
Old Fang took it and looked at it once, but didn't say anything.
The numbers on the paper were neatly arranged in rows. The inner diameter was measured three times, the ellipticity was calculated to be 0.01, and the wear of the bearing outer ring raceway was also listed in a separate row.
After he finished reading, he returned the draft paper. "Disassemble the bearing housing and measure the ball bearings."
Ding Haifeng reached out to pry open the retaining ring on the bearing housing.
The circlip was very tight. He used circlip pliers to hold the holes at both ends and squeezed hard. The circlip popped out and fell under the old parts rack, bouncing twice before stopping.
He flipped the bearing housing over, caught the ball bearing cage in his palm, and pulled the ball bearing cage and the balls out together. There were nine balls in total. He held them up with cotton yarn and arranged them in a row under the windowsill.
He first roughly measures each ball with a vernier caliper, then remeasures it with a micrometer, and picks out any ball with an error exceeding 0.01.
Two of the nine ball bearings are elliptical, and the remaining tolerances are all within the allowable range.
He wrote down the data on a piece of scrap paper, and when he finished, he looked up and said, "Master Fang, two of them are substandard. The remaining seven are usable, but their pressure resistance needs to be reduced by one level."
How much will it be reduced?
"The original rated speed was 3,000 RPM, so we'll downshift to 2,500 RPM."
Old Fang took the cigarette out of his mouth, nodded, and said, "Write it down in the register."
Ding Haifeng placed the waste ball bearings in a small iron box, which made a soft metallic clanging sound when the lid was closed.
The remaining seven usable pills were carefully recorded in the register, the handwriting small, but each stroke perfectly placed within the grid.
He wiped the micrometer with cotton yarn, gently put it back in the toolbox, and after closing the lid, he opened it again to check that the micrometer was free of hand sweat before finally securing it.
Hong Xiaobing was squatting at the entrance of the used parts warehouse, retrieving old parts from the diesel drum. He had already retrieved the bearing housing and coupling, and was now wiping the third old flywheel with cotton yarn.
The flywheel was covered in thick grease, and he couldn't remove it after wiping it twice. So he changed to a piece of coarse cotton yarn, dipped it in diesel fuel, and scrubbed it vigorously until the flywheel's surface revealed the gray-iron body underneath.
Ding Haifeng found a scrap bolt on the shelf and used the bolt head to help him remove the hardened grease from the flywheel keyway.
The sludge had dried to a hardness like stone. When you tried to scrape it off, only a small piece of powder came off. Ding Haifeng used the tip of a bolt to pry the bottom of the keyway three or four times before he could clean it completely.
"Thank you," Hong Xiaobing said.
He glanced at the pile of data Ding Haifeng had just measured and the usable ball bearings he had identified, scratched his head, and said, "You measured so meticulously. There are hundreds of parts in the old parts warehouse; are you going to measure them one by one?"
"The water pump is ready to be measured." Ding Haifeng put the micrometer back in its box and squatted down to help him move the cleaned old flywheel onto the shelf.
The flywheel was heavy, and two people each supported one side when it was moved. When it was placed on the shelf, the shelf was slightly bent under the pressure. Hong Xiaobing picked up an old wooden board from the ground and placed it under the shelf to support it.
He stabilized the flywheel and continued, "The refurbished water pump operates at a high speed, so even the slightest difference in clearance is unacceptable. If it's installed too close to the mark, the bearing will burn out, and we'll have to come back to repair it. That would take more time than we're currently testing a hundred bearings."
Hong Xiaobing didn't say anything more, squatted back down and continued wiping the next old item.
At the entrance to the kitchen, Lin Xiu'e brought out the second steamer of sweet potato chips that had been steamed that morning.
There was still a small half-bag of dried sweet potatoes left from her aunt's gift. She spread the dried sweet potatoes on the steamer rack, and the steam coming out of the gap in the pot lid was blown along the wall by the sea breeze.
She tested the texture of the dried sweet potato with her finger, picked up a piece with chopsticks and tasted it. The sweetness and chewiness were just right. She then took the steamer off the stove and placed it to cool.
Old Sun sat under the loquat tree, took out his pipe from his cloth bag, stuffed tobacco into the bowl, packed it tightly, lit it with a match, and took a puff.
The smoke was dispersed by the sea breeze, drifting among the loquat leaves and slowly dissipating.
As the sun climbed directly overhead, the shadow of the loquat tree in the yard shrank into a small ball.
The broken seashells were bleached white by the sun, and the leaves of the largest loquat tree were thick and rustling in the sea breeze.
Ahai's diesel engine had been running under load for more than half an hour, and the water pump's output showed no signs of slowing down. Aguang, lying on the workbench, turned to the last page of the sixth register and filled in the specifications of the newly added old flywheel in the blank column of the last line.
The pen scratched softly as he wrote the last word. He closed the register and rubbed his eyes.
Ah Hai stood up from beside the diesel engine, wrote down the water temperature and oil pressure data in his notebook, and called out, "Master Fang, water temperature is 78 degrees Celsius, oil pressure is normal."
"Keep an eye on it, run it for a full hour." Old Fang walked out of the old parts warehouse, stood at the workshop door and glanced inside.
Ding Haisheng squatted in front of the thick steel plate, finished welding the third overhead seam, put the welding gun aside, took off his mask and stood up.
His face mask and goggles were covered in tiny welding slag particles, which he wiped off with cotton gauze.
Jiang Haiping squatted under the loquat tree, folded the half-old newspaper back into the ledger, stood up, and patted the dirt off his knees.
He went into the used parts warehouse and looked through the bearing data that Ding Haifeng had just measured from beginning to end.
I picked up the micrometer box to check if the lid was securely fastened, then picked up the record book and tapped the line "Rated speed down one gear" with my fingernail.
"Incorporate this data into the water pump refurbishment plan."
Ding Haifeng nodded.
He reinstalled the old bearing housing, pressed each ball of the ball bearing cage back into its original position, inserted the snap rings into the slots, and pushed them into place with snap ring pliers.
He placed the assembled bearing housing in the labeled compartment on the shelf, stepped back to check it, and only after confirming it wasn't crooked did he turn around, pick up the vernier calipers, and continue measuring the end face runout of the next old flywheel.
The white tape with the word "Peak" on it on the caliper handle was already frayed from sweat.