An expert heat treatment and comfortable ergonomics go a long way.
A Lesson in Chemistry
When designing knives, Tommie Lucas jokingly thinks back to his high school science classes. Specifically, crafting blade steel relies on a formula for desired hardness, edge retention, and other factors.
“It’s total nerd, chemistry stuff,” said Lucas, a self-admitted knife nerd.
For reference, designers always keep a handy steel chart nearby. It lists common elements that make up different steel types. Think of a periodic table tailored for knife craftsmen. Common elements include carbon, vanadium, and tungsten. Each material adds different characteristics to the steel alloy — which is important for knifemaking. They can benefit anything from strength to corrosion resistance.
The best properties of these materials are revealed when the blade undergoes a vital step: heat treatment. During this process, the steel is heated and cooled, which benefits the blade in a variety of ways.
An expert heat treatment adds high performance to this stunning Premier blade.
The initial heating and cooling stage adds hardness and durability to the steel. However, too much hardness makes the blade brittle. A second phase, called tempering, heats and cools the blade again. This step softens the steel to the ideal hardness and brings out more steel properties.
Speaking of steel properties, heat treatment plays a big part in improving them. Heating the steel causes the ingredients to melt and mix together. This blend creates carbides: a compound formed between carbon and another element. The cooling process locks these formations in place.
After that, the sawtooth-shaped carbides serve as your main cutting source along the edge. You can’t see them, but if you examined the edge with a microscope, you would see tiny serrations. Of course, carbides take a lot of wear and tear, eventually breaking away. That’s where sharpening comes in. When sharpening, you reveal more carbides that were previously hidden within the steel. With a good heat treatment, carbides will act as excellent cutters for a long time.
Kai is well-known for its expert heat treatment. Without this skill, performance suffers.
“A company can buy the best steel,” Lucas said. “But if they heat treat it improperly, they’ve wasted their money. Just because a knife claims to use a certain steel, that doesn’t mean it was treated correctly.”
If this happens, the blade loses hardness and edge retention. That’s why attention to detail is so important. Kai engineers have a keen eye for the little things that set Shun apart.
Fine Tuning the Design
Each Shun features versatile handles that are great for many hands.
When judging how comfortable a knife is, most people think about hand size and how it fits around the handle. However, Lucas explained that knife comfort is so much more than that.
Many people overlook work height when creating a knife. Shun experts kept this in mind when they originally designed the knives for the US market. They will often change blade geometry based on how tall the average American is.
“When making knives, humans are the interface that we have to work with,” Lucas said.
Handle design is important, too. Lucas keeps in mind grip fatigue, comfort, and how a handle shape affects blade impact. To improve these factors, he has learned about Japanese ergonomics. According to this philosophy, the most comfortable handles allow you to switch grips often.
“Ergonomics were meant to move,” Lucas said. “If you hold a handle in the same spot for more than ten minutes, it’s no longer ergonomic. It’s actually damaging you.”
Most Eastern handles are designed to be simple, usually featuring a tubular shape — or something similar. Curvy designs are usually avoided.
Shun continues this tradition for American users. Handle shapes do vary by series, but each of keeps a simple design. The Classic series, for example, benefits from a comfortable, D-shaped handle.
All of these factors teach us an important lesson in cutlery. What you can’t see is just as important as what you can see. To get the best of both worlds, it’s best to go with a trusted brand. Kai craftsmen have made bladed tools for over 110 years. While some may imitate the Shun style, they can never capture the fine craftsmanship that goes into each knife.
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