Sharpness and hardness

Ah, E3 time. Rather than discussing video games, the developing companies that had lacklustre shows and CGI shows, let’s discuss something that has actual impact on your life; knives. I can already hear certain Australian groaning, but this is a little different than what I usually go about.

Having a sharp, usable knife in your daily live is a life saver in many ways. There’s a lot of unseen things that you find a blade useful, and not just opening mail letters and packages. A good blade is a completely usable replacement for scissors, for example. It’s all about small things really. Of course, carrying a blade with you might be ill advised or even illegal, but not let’s get to that. In all honesty, modern society is far too concerned about knives even with all the cultural differences. They are first and foremost tools to be used against something else than people. If you want to hurt people with blades, there’s far better options than just your damn switchblades. Never bring a switchblade into a fight, you’ll most likely end up chopping your own finger off.

Where most people will meet the need for a good knife is in your kitchen. If you like to cook a lot, it’s a no brainer thing to get a good set. For an everyday use at the generic consumer level, there’s two basic materials that are available; metal knives and ceramic knives. The two have very different how they work, even thou both cut just as fine as the other. There’s the issue of design in the blade and how well it is able to cut whatever it is meant to cut.

To simply put it, the main difference between metal and ceramics is hardness in material. Most cheap knives are of pig iron with a chrome layer on top, which is a great way to cut down cost and make the consumer buy new knives faster. Finnish Mora knives are made like this, and their low quality is both visible and you can feel it the moment you grasp its cheap plastic handle. Putting some money into a good knife set will yield you longer life on the knife and thus savings on the long run. Of course, neglecting basic knife care will yield you dull and rusty blades. The metal knives with stainless steel have hardness of 6 mohs, to make a very crude simplification. The actual hardness depends on what materials have been used to make the steel, and it can go both ways. Often knives can go up to 7, or in some cases, up to 8 mohs. Some knives are specialised in how they bend, and these knives have lower hardness, as the harder material is, the less elastic it is. Ceramic blades’ idea is that they’re harder than this and go from 8 mohs and up.

The mohs scale is ordinal, and the harder materials are always notable more harder than the last. Diamond is 10 at the top of the hardness scale, and there’s some materials that are harder than that. From fiction, we can take the Destroyer-Class BETA as an example of harder material at 15 mohs, and that’s all sorts of silly. In fiction the writers often forget all the downsides of the harder material. Ceramic blades, while they’ll stay sharp far longer than their metallic counterparts thanks to the more penetration the hardness gives to them, they can’t be used in anything that would require the blades to bend or give in as they shatter.

Ceramic knives have certain level of transparency in certain brands and models
Ooh, milky see through. Also, never hold a knife like this for safety reasons. Now that I think of it, why didn’t I put the camera on the tripod and use both hands? Sometimes you just don’t stop thinking these things all that well

I will admit my bias for steel knives as they do not tend to shatter, unless they’re heat hardened or have been under dubious circumstances. Usually they’ll just get nicked and banged up, sometimes just snapping, but never shattering as such. The thinness of the ceramic knives do worry me. However, the time I’ve been working with these ceramic knives I’ve noticed that in actual cutting they’re no less worse and do manage to keep up with the hardness surprisingly well. And yet, every time I cut something I need to be more careful how I cut.

The ceramic knife is a bit overkill, really. It’s designed to be harder than anything you might meet in the kitchen, be it meat or bone. Ceramic knives are meant to be used in the optimum situation with little variation. Cutting against anything else than wood or plastic cutting board is not recommended, and they’re not really transportable either. The metal knives on the other hand can be used pretty much anywhere in any situation, and while they dull faster, they’re also miles easier to sharpen. Of course, certain tools have their best uses in different places, and it is always recommended to get the proper tool for a certain job.

Nevertheless, in everyday use the difference between the two are up to preference and the differences they have is not too large, when somebody just takes care of how the materials are cut and the knives are taken care of. There are some preparations that can’t use a ceramic knife, like filleting a fish, where a knife that is able to bend, even if slightly, is far superior option to the rigid of ceramics. There’s also a limit to the variations of ceramic knives. Overall, there’s only handful of usable lengths, widths and shapes a ceramic knives can have in comparison to the endless possibilities the steel offers. Of course, the best knife in the world would be mathematically absolutely sharp and as thin as possible to secure the finest cutting result as possible. However, the day when we will have knives that are able to cut material on a molecular level are on the store shelves for all people to purchase is still just science fiction.


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