A Wheel That Wobbles

First, loosen the soil, then dig a small trench to channel the river water in. It immediately turns into muddy ground, but this mud isn't suitable for making brick blanks yet; it needs to be trampled into mature mud.

In the past, this mud-trampling work was done by oxen if available, or by people if not. Luo Chong, however, was more unconventional and used elephants directly.

Rou Rou and Hui Shan, these two little ones, were still young and playful. Especially this mud-trampling activity – it seemed to have a natural attraction for creatures like elephants. They rolled and galloped through the mud, having a blast and treating the work as a game. It was hard to get them out; their attachment to the mud was even more stubborn than a wild boar's.

Only after finally luring them out with sweet roots did these two turn into mud elephants. He then took them to the river for a bath before sending them off to rest.

Rou Rou and Hui Shan's work was finished, and the human work began. The trampled, mature mud was placed into molds and pressed down, turning into brick blanks, piece by piece. Then they just needed to be left to air dry.

This was just the process of making brick blanks. Luo Chong wasn't planning on firing bricks now. The brick firing could wait until winter. In winter, everyone was idle with nothing to do, and firing the brick kiln would be very warm, making it a pleasant job, definitely much happier than firing bricks in the summer.

The bricks were large. This batch of large bricks was intended to wrap the rammed earth city walls, so there was no need to make them too small.

However, the work progress was much slower, not because of the time spent pressing the brick blanks, but because most of the time was spent transporting the mud and brick blanks.

The bricks for building the city were 40 centimeters long and 20 centimeters wide and high, a standard rectangular cuboid. But they were extremely heavy. A wet mud brick this size weighed at least thirty to forty catties. One person could only carry one large piece of mud with a woven basket or carrying pole at a time, then transport it to the drying area for pressing and drying.

People were exhausted, and the work efficiency was low. Therefore, a convenient and fast means of transport had to be created immediately.

Thinking of transport, naturally, it had to be something like a cart. It saved effort and the loading capacity would increase exponentially. And the soul of something like a cart was the wheel.

Given the current conditions, Luo Chong basically had no other choice; wooden wheels were the only option. But how to make wooden wheels was a problem.

In his previous life, Luo Chong had changed tires on cars and repaired tracks on tanks, but wooden wheels, he had only ever seen them on television.

He remembered that this type of wooden-wheeled cart was basically impossible to find in China. Even if he occasionally encountered a horse-drawn cart, it used rubber tires. Only the British Empire still kept quite a few of these antique items, especially the Queen's carriage.

The main structure of a wooden wheel should be in three parts, similar to a bicycle wheel, just without the tire. A circular piece fitted onto the axle – Luo Chong didn't know what that thing was called in ancient times, so he'd just call it the wheel hub, it was easy to understand. Many wooden spokes would be inserted into the wheel hub for support. On a bicycle wheel, they were called spokes, and Luo Chong would also call them spokes. Finally, there was the outer wooden ring, which was the most difficult part of the wheel to make.

He had learned in Chinese class 'Wood straightened by the string is bent into a wheel,' meaning ancient wheels were made by bending straight wood and then baking it into shape. But no matter how skilled the ancients were, they couldn't directly bake a straight piece of wood into a complete circle. So, wheels were generally made in sections.

Wheels with smaller diameters used at least two sections of wood for the outer ring, or three sections. In any case, the more sections there were, the smaller the arc of each section. This broke down a circle into multiple arched segments. A circle is hard to bend, but an arch is not a problem, otherwise how would longbows be bent into curves.

Luo Chong had never seen wooden wheels being baked, but he had seen oak wine barrels being baked. Wine barrels were usually made by bending and baking oak planks into shape, and Luo Chong was going to use oak to make wheels.

A new project was starting, and finding apprentices was naturally the first step. In the Han Tribe, Mutong was the most talented woodworker. The fact that he could figure out how to use red-hot charcoal to burn a barrel shape into a log meant he was no ordinary person.

Another was Wooden Porpoise. Wooden Porpoise was a very honest person, didn't like to interact with others, and wasn't very strong in combat. He didn't have any particularly outstanding characteristics, but it was precisely such a quiet person who, if focused on one thing, would achieve great things. So Luo Chong also called him over. From now on, the two of them would be the Han Tribe's dedicated woodworkers.

He had assistants, but the main work was still done by Luo Chong himself. After all, asking others to calculate pi wasn't realistic; that would have to be taught slowly later.

The Han Tribe's first vehicle was a wheelbarrow built based on practical needs, mainly for transporting mud. It had a pair of wheels in the front, two legs in the back, and two long handles. It was a push-type two-wheeled cart, similar to the cement carts used on construction sites today, but entirely made of wood.

The wheels weren't big, only 70 centimeters in diameter, incomparable to the ancient large wheels that were as tall as a person. The wheel hub was made directly from a section of log. The center of the log was directly pierced with a red-hot copper rod, then enlarged with a hand drill and smoothed.

Then, connection points for the spokes were evenly spaced around the outer diameter of the wheel hub. The holes were still made using a red-hot copper rod and a hand drill, just to increase production speed.

The outer ring of the wheel was made from two sections of baked oak, roughly two semicircles. Baking oak also had its techniques. The side with the bark should be on the outside because the wood layers near the bark are harder. Putting it on the outside made it more wear-resistant, and the heartwood material was softer, suitable for being compressed and shrinking inward.

First, the sawed oak strips were soaked in water and then placed on a pre-prepared thick log for shaping. Then, a rope loop made of thick hemp rope was used to tightly bind the oak strips to the log. Finally, a lit pottery basin was placed underneath, heating it with fire while tightening the rope loop with a wooden stick, causing the oak strips to gradually bend and take shape.

It took the three of them a whole day to build this small wheelbarrow. The wheel only had 10 spokes, and even these were planed out one by one with a planing knife. It was too slow. Luo Chong planned to improve the process next time.

The two sections of oak in the outer ring were fixed at the joints with U-shaped copper nails. The axle was also wooden. It rolled fairly smoothly. On top was a wooden hopper, with all the joints using mortise and tenon structure. Aside from the four copper nails used on the wheels, the rest was entirely wood.

The first small wheelbarrow was built and immediately delivered to the construction team for use. Luo Chong was also experimenting and observing where improvements could be made.

After the first day of use, the tribesmen were very interested in this new mode of transport. Since Luo Chong had invented weaving baskets, the Han Tribe had finally said goodbye to carrying things on their shoulders and in their hands, changing to carrying back baskets or balancing things on carrying poles. Now, with the appearance of carts, this would be another reform.

The tribesmen were very happy, but Luo Chong was not optimistic. Because the tools were primitive and crude, this small wheelbarrow could be described as roughly made. Its performance could only be said to be 'able to move', meaning it would roll when pushed, but it would definitely fall apart before long.

There were too few spokes. Ten spokes were simply not enough to support a circle. Ancient wheels had over twenty or thirty spokes. With fewer spokes, the outer ring couldn't maintain its circular shape. When the load was heavy, there was a risk of the outer ring cracking or deforming.

Also, the width of the wheel hub was insufficient, and the length of contact with the axle was too short, causing the wheel to wobble left and right when rolling. The wheel hub would need to be lengthened next time.

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