The old things I repaired have become fine

Chapter 28 Who can tell me how to make this ghost ball?
An ordinary electronic scale, even a food scale specially designed for weighing small weights, would not be able to weigh something this small - the reading would probably not even show a correct value.

Shen Le hesitated for three seconds between "ordering a precision balance" and "finding someone to borrow one", but finally opened Taobao.

A domestically produced electronic analytical balance with a ten-thousandth of a gram capacity costs 630 yuan. An imported one costs 0.01 to yuan at its cheapest. Of course, the daily sale store sells one with a claimed accuracy of gram for only yuan. Do you dare to use that?
His current fixed monthly income is 100 yuan per day from Tianxianglou, half of which he gets with Pinocchio, leaving him with 1500 yuan. He also tours various schools, with 22 working days a month, 1100 yuan per day, half of which he gets with Pinocchio, leaving him with yuan. yuan is enough for his own food and daily expenses, so he can spend lavishly on buying instruments, then...

Shen Le thought for a moment, picked up his phone, and flipped through the address book. After flipping through it, he called police officer Shi Guangbing:

"Hello, are you there? Can you help me?"

It must be admitted that local tyrants are local tyrants.

Shi Guangbing made a few phone calls and, relying on his local connections, he actually helped Shen Le borrow the right to use a precision balance. Soon, he called Shen Le and asked him to bring the items that needed to be tested to a certain testing center:
"What? You want me to come over? Can't you just borrow it?"

"You think too much!" The police officer on the other end of the phone laughed and scolded:

"What kind of precision is a one-ten-thousandth balance? Can it be moved casually? Not to mention that it can't be moved, the table on which the balance is placed is shockproof, and the temperature in the weighing room must also be kept constant, otherwise it will affect the precision! Hurry up! The inspector is my girlfriend's classmate, otherwise I won't help you!"

"Good good..."

Shen Le agreed readily. He wiped the ghost ball carefully, picked up the spray gun, and blew hard inside for a while, blowing away the dust inside the three-layer ghost ball, and took it to the testing center the police mentioned. When they got there, they were not allowed to enter the testing room, and could only watch through the glass on tiptoe:

The inspector was wearing a neat white coat, a work cap and a mask. She took the bag of ghost balls from her hand, turned back to the weighing table, reset the scale, and took out a...

tweezers?

Well, you are indeed a testing center for precision balances. What are the light and small things you test on a daily basis?

The inspector held the ghost ball with tweezers, passed it through the opening of the glass cover of the balance, and placed it on the central scale pan. The display screen in front of the electronic balance flashed, and a reading immediately popped up:
0.6867...

Shen Le covered his face. Very good, very good, it is accurate to four decimal places, very impressive!

He thanked the person profusely and begged him to help measure the volume. He used the immersion method to measure the weight of the solution in the test tube twice, and the answer he got was:
About 0.85 cubic centimeters.

...That is to say, the density of the wood used for this ghost ball is 0.78g/cm. Shen Le looked up the common wood density table for a long time, but could not get the point:

Oak, walnut, maple, and even jujube are all in this density range. As for the hardness of wood, it is really impossible to measure it by manual measurement...

"So what kind of wood should I use?"

Shen Le gnashed his teeth, feeling entangled in a dilemma. In fact, he could just find a suitable wood, or even order a suitable ghost ball online now.

The price is not even expensive. A 15mm diameter mammoth tusk ghost ball is only 145 yuan on Taobao, and a deer antler ghost ball is even only 50 yuan.

However, Shen Le always felt that the more work he did, the more likely it was that the ink fountain would develop intelligence and become a...

Although he also didn't know what the inkstone would become if it had a soul, would it become a carpenter?
Shen Le sighed, and finally took out his phone to contact his senior from graduate school:
"Brother, I remember that you were doing a PhD project to study the materials of various ancient buildings?" "Yes, yes," the brother was obviously exhausted by the project. When he was poked by him, he sent a long text to complain. There were several homophones and a lot of punctuation misplaced. It was obvious that the voice input was directly converted to text:

"I'm working on it now. I'm exhausted! I'm running all over the country, climbing up and down to collect samples. My legs are so thin! I also have to ask people for help everywhere, asking my fellow students to help me collect some samples and send them back... By the way, what's the matter?"

"Brother, I remember your project seems to be cooperating with the Forestry Bureau to test the DNA of various woods to see what kind of wood they are? - Can I get a ride? I happen to have something to test..."

"Okay! Send it to me!"

"Thank you, Senior Brother! How much?"

"It's free! A single test is not expensive, only a few dozen yuan. The difficulty is that most people may go there and they may not do it for you. Just put it in the project and do it together. Anyway, there is project funding..."

The senior brother sent an address and fell silent again. Shen Le breathed a sigh of relief, took photos of the ghost ball, took photos from multiple angles, made rubbings, and used plaster to cast it. After completing a series of tasks, he held his breath and carefully took a sample:
"Brother, it's up to you!"

God knows, he knows where to go for a paternity test, even though he doesn't have a paternity test to do. Identifying the DNA of Mu Mu was really difficult for him, but fortunately his senior brother was helpful!

After sending the sample, Shen Le began to study how to make this ghost ball. First, he opened CNKI and searched——

OK, with “ghost ball” as the keyword, there is not even half a paper.

Shen Le was not discouraged and continued to work hard. He opened Taobao, Bilibili, Douyin, and Xiaohongshu and searched for them one by one:

"Uh... this only shows the finished product, not how it was made."

"Hey... where's the key step? Where's the key step?! I fast-forwarded dozens of times, but still missed 2/3 of the key steps. This is unacceptable, sir!"

"This... well, what can you see from a 15-second video?"

"This... what is this? CNC machining, a 12-sided exquisite ball? So it can be done using CNC machining? - Just tell me how to do it!"

Shen Le spent a full half day immersing himself in searching for various materials, but in the end, he only came to a vague conclusion:

The key is positioning. On the surface of the sphere, position it well, make a few circular holes, then carve it layer by layer, and finally carve it layer by layer. But how to position it? How many holes to make? How deep to carve?
The first two questions can be answered by measuring the ready-made ghost ball. However, how deep to cut is another matter...

Shen Le sighed. Helplessly, he reached for his phone and called again:
"Senior sister, are you there? Help me!"

　The above CNKI, Taobao, Bilibili, Douyin, and Xiaohongshu are the process of cats looking for information... If you have any other sources of information, please recommend them...

　　Meow meow, please comment, please comment a lot, please comment of all kinds...

　　The cat will show you how the protagonist makes the ghost ball!
　　

(End of this chapter)