The more Yang Hao wanted to do something, the more he felt: it was too difficult to do something he was satisfied with in this era.

He just wanted to make a surveying and mapping tool that was almost available. He found that everything had to start from scratch.

First of all, the ruler is definitely not available.

He had to make one by himself, at least a millimeter-like ruler. And after it was made, it could only be said to be barely usable.

When he made a millimeter scale ruler, he scratched his head a little.

Because he couldn't think of a way to accurately divide a length into ten parts.

He is a persistent person.

After thinking for two days, he finally came up with the stupidest way.

That is to use the principle of a vernier caliper to reverse the reversal.

The vernier caliper's vernier should be 90% of the length compared to the main ruler.

So he planned to determine the scale of the vernier caliper first.

In fact, the ancient rulers have never been accurate.

In other words, each place has its own objective or subjective errors.

He plans to make a 50-degree caliper vernier first. Then the total length of the vernier caliper scale should be set to be four inches and nine minutes.

But now there are also rulers that are accurate enough to score.

Yang Hao found a handful of this at his home.

He first chose one of them as the "standard ruler", and then estimated the "0.98 minutes" thickness to use this as a standard for determining the scale of the vernier caliper.

Of course, it is definitely not accurate enough to see with the naked eye. Finally, after he determined the vernier fifty scales, he found that the total length slightly exceeded the "4.9 inches" of the standard ruler.

Therefore, after using the standard ruler, it can be thrown aside. The standard no longer exists.

But it doesn't matter.

He can set his own standards.

He first roughly estimated the standard of "one point", kept making rulers, and combined them with vernier to form vernier calipers.

When the estimated ruler measured various lengths and just matched the measurement results of the fifty-degree vernier caliper, he made a ruler that was accurate to the point.

What he made was two or three minutes longer than the one in his house.

But it doesn't matter.

Because, this is just his own standard.

Anyway, he already has a vernier caliper with an accuracy of 0.02 points.

Although it is still very rough and the accuracy is only equivalent to 0.06 mm, in this era, it should be the most accurate length measurement tool.

It was the process designed that made him dizzy. His west wing was also full of wood chips.

My family almost thought he was going to change career as a carpenter.

"Brother Six, my father asked me to ask you. Can you buy all the things you purchased?"

Yang Bode slapped his head.

He even forgot about the procurement task assigned to him by Yang Bode.

There are two more days when you have to put on a big mat. It will be too late to not buy anything.

He hurriedly said, "I'll go find it now and see what else is there at home."

Yang Zhao saw that there were many tools in the room and the ruler with different lengths of the table: "Brother Six, what have you been doing recently?"

Yang Hao smiled and said, "Rulle. Don't underestimate these things. Just rely on these things, I may be able to be remembered forever."

"Brother Six, you have made the 'Wufeng Plough' and you can be remembered forever."

Yang Hao laughed and said, "You don't understand even if you say it."

He changed his clothes and said, "I'll go to the warehouse to check it out. There should be a lot of things on the list. If not enough, I'll go to Chang'an tomorrow."

Most of the things that Yang Hao needs to purchase are for food and use, such as fresh vegetables and fresh meat.

It's hard to take out those things.

Only go to purchase.

As for other things, you can steal the day and change the day in his warehouse.

He even made some things he needed to use, and even some of them were not on the list, such as dried shrimps, dried squids, strips, yakini and other dried seafood products.

As for abalone and sea cucumber, he also has a lot of them. But he doesn't want to take them out.

That's too much of a show of wealth.

As for vegetables and meat, I can only order them now and send them to you when you are in the future.

So he immediately changed his mind and planned to go to Chang'an immediately.

The vernier caliper just completes the main ruler and the vernier scale, but it is not done well.

After all, he is not a carpenter.

I happened to go to Chang'an to find a skilled craftsman and make a real vernier caliper.

He first took the things he took out to the kitchen, and then reported to Yang Bode.

Yang Bode looked at the sky for a moment: "I'm going to Chang'an now. I'm afraid the city gate will be closed when I go to Chang'an."

"I'm rushing on the way, so I should be able to come before the gate of the city."

After hearing what he said, Yang Bode knew that he was determined to go: "Then take Hequanshan, if you can't get there on the road, you can take care of yourself when you live outside the city."

Yang Hao answered, not only called He Quanshan, but also called his dog-legged Xi Junmai.

He rode a donkey with a vernier ruler and a long ruler. He Quanshan and Xi Junmai did ride in a carriage.

I ran all the way and didn't stop for a moment.

When I arrived in Chang'an, the sun had not yet set.

After entering the West City, Yang Hao saw that there was still some time, so he said to Xi Junmai: "You go to the inn we stayed in before and book two wing rooms. I'll go to the blacksmith shop in front."

Xi Junmai led the donkey and drove the carriage to go there quickly.

"It's getting late." Yang Hao said to He Quanshan. "Let's leave too."

There is a blacksmith shop with a large shop in front. From outside the door, you can see hunting knives, kitchen knives and farm tools hanging inside.

He Quanshan said: "What are you going to beat?"

"I want to hit a few rulers."

Punching a ruler?

He Quanshan felt it was inexplicable. Do you have to use iron to make a ruler?

Yang Hao ignored him and went in and called someone. A bronze man came out from behind: "Does the guest official want to buy iron tools and make things?"

Yang Hao took out a ruler and said, "I want to hit something."

"What is this ruler?"

"I just want you to help me draw a ruler. I've painted it. See if I can do it."

Take out a few pictures, divide them into parts and the overall picture, and the dimensions are also marked on them.

It looks basically the same as a modern vernier caliper.

This thing must be strange to people here.

So Yang Hao had to explain clearly to the blacksmith: "This is mainly divided into two parts, which can be installed just right after each is made. It can slide but it cannot be too loose. Maybe you can type it out?"

The blacksmith nodded and said, "Things can be beaten."

"I have marked the dimensions on the drawings. But this size must be made according to my ruler. Just use this long handful."

"Can."

"It must be smooth and smooth, especially here." Yang Hao pointed to the two measuring claws on the upper and lower sides of the picture. "When the two components are held on the head, the upper and lower sides must be tightly sewn and the upper and lower sides must be the same line. As long as the straight line is perpendicular to the ruler's body, it is possible?"

"This work will probably take some time to do it."

Yang Hao said: "It is made of copper. Copper is softer than steel and is easier to polish."

It's easier to scale.

"Okay. Just use copper to beat it, the price is..."

"When will you do it well, and how much does it cost?"

"I'm afraid it will take a lot of copper to make this. In two days, the workload is three stakes."

Yang Hao shook his head: "I'll give you five stakes, maybe you'll play well tonight?"

The blacksmith suddenly looked up and said, "Yes. I can stay up late."

Yang Hao smiled and said, "Okay. But after you finish it, you will help me make a ruler on it tomorrow. You can also follow the lines on those two rulers. Are you sure you can do it?"

The blacksmith looked at it for a while and nodded, "This is OK."

Yang Hao took out a small gold and said, "This is considered a deposit. I will come over and make a ruler with you tomorrow at noon. But the things are not done well. I won't want them."
Chapter completed!