Chapter 99 (1/2)

Shi Xiong's ”carefully modified” smelting process has really played a huge role, because after the full oxidation and decarburization of the hot metal, the steel produced by this furnace is exactly the steel, and according to Shi Xiong's general judgment, this batch of steel should belong to the category of medium and low carbon steel.

Although medium and low carbon steel is not as hard as high carbon steel, its toughness is better. In daily life and even military applications, medium and low carbon steel is far more widely used than high carbon steel.

Moreover, medium and low carbon steel can also be processed by heat treatment process. The surface hardness of the processed workpiece is very high, and can even be used as high carbon steel.

Although Shi Xiong didn't know much about the heat treatment process, he had heard about it in general. So he told Lieutenant Ferguson what is annealing, tempering and quenching. After these heat treatment processes, he let the little brother go to experiment by himself.

Anyway, there's enough steel from this furnace, enough for Lieutenant Ferguson.

However, it is obvious that major Ferguson is not in the mood to deal with the steel that has just been refined. He is now working with the wood family to make a wooden lathe for rifling.

Yes, the first meaningful thing that lieutenant Ferguson did after he came to the high tree tribe was that he and the wood family made a wooden lathe specially for rifling the barrel of the gun.

This is a very backward lathe in the eyes of stone bear, and the power is neither water nor steam, nor electricity, not even the most basic animal power, but pure human power.

However, it is indeed a lathe, even if it is very simple and primitive, but it is still a machine tool to the letter, because the use of this simple equipment can complete the work of rifling the barrel.

This lathe is very long, three meters long. In fact, it is a wooden frame, on which two very flat and straight wooden guides are laid. A wooden slide table that can fix the hook knife is erected on the guide rail, and between the two guides is the fixed position of the barrel.

The name of this strange lathe is ”manual wooden broaching machine”, and the core part of this broaching machine has three parts, one is the hook knife specially used to pull rifling, one is the pull rod screw connecting the sliding table and hook knife, and the other is the most complex linkage mechanism, which is the core part involved in the uniform rotation of the barrel.

Hook knife is the core part of rifling. It's a knife. In fact, it's so simple that stone bear can't bear to look directly at it.

The hook knife is actually a steel bar slightly smaller than the inner diameter of the barrel. This steel bar is also cast, and there is a groove in a specific part, which is used to clamp the steel sheet with increased strength after quenching. The steel sheet is made by hand, and there are one or two protruding strips with a certain inclination angle on it.

Because it is handmade and quenched, the surface hardness of the steel sheet is much higher than that of the barrel. In this age when there is no high hardness alloy steel, we can only use this method to replace high hardness alloy steel.

This combination is hook knife.

Another core part of broaching machine is the pull rod screw connecting the hook knife and the sliding platform.

Screw has a long history, the earliest can be traced back to around 400 BC. However, modern screws appeared in the late 19th century, so in this era, screws are extremely precious and difficult to build.