Misunderstood Coarse Stone

by Sami P., 22.5.2023

I have often said that the second purchase from my store for hiomakivi.fi customers is frequently a coarse sharpening stone. This happens because the common first purchase includes stones with grits of 1000 and around 3000. Buyers of these stones are often surprised at what they can ultimately be used for. A 1000 grit stone alone is not sufficient to repair a knife with clear visible damage or a blade that has become blunt, also known as "going round."

When I talk to customers daily and answer their questions, the same topics about coarse sharpening stones often come up. I notice that coarse stones are often viewed with hesitation, and it is commonly believed that many sharpening stones are too coarse for their needs.

With a bit of caution and common sense, I say that a coarse stone can never be too coarse – but it can certainly be extremely uncomfortable to use.

There is often a fear that excessive grinding will remove too much material and possibly make the blade's profile uneven. Another common assumption is that it is difficult to remove the marks left by a too coarse stone.

There is some truth behind these concerns, but the final truth often reveals itself during sharpening; it is discovered that the stone was not as aggressive as imagined, and the marks can be surprisingly easily hidden with a 1000 grit stone. The toughness of the metal plays a significant role in sharpening, so even a slightly higher quality knife will always need a coarse stone when repairs are made.

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Naniwa Chocera Pro 400

54,00 €

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SUEHIRO Debado LD-21 #180

56,00 €

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A coarse sharpening stone is soft, and for good reason.

"In this context, it's important to note that we are talking about high-quality Japanese sharpening stones. Let's forget about the cheap, often Chinese stones that are nearly unusable due to their softness and inefficiency."

I often encounter comments that the sharpening stones in use are soft and wear out quickly. It's easy to respond to this comment by saying that this is exactly how they should work – otherwise, effective sharpening wouldn't be possible!

There are many types of coarse stones. Some are sand-like soft, very effective stones that require a bit of learning to use effectively. Perhaps the best example of this is the Imanishi WZ400. It is a very large, effective, and heavy stone that lasts a long time in use, even though it is soft. This stone is a prime example of how a coarse and soft stone works at its best: When you start sharpening with this stone, it feels like nothing is happening at first. But when the surface of the stone finally opens up, it feels like the brakes are being applied, and you can clearly see the metal starting to come off.

Then there are coarse stones at the harder end of the spectrum – for example, Shapton Kuromaku stones 120 and 220. These two are good examples of effective, coarse stones that work well with all metals and are relatively hard. However, they can still get deep scratches when doing intense work, such as sharpening the tip of a knife.

So, my basic guideline is: A coarse sharpening stone is always at least somewhat soft, but it's soft for a reason. Softness brings efficiency. If a soft sharpening stone feels strange to use, it might be worth investing in a diamond stone like the Atoma 140. This way, you get a hard sharpening stone to use.

There are speed differences in coarse stones.

This guideline does not apply only to coarse stones but is the greatest challenge in the entire sharpening stone industry. Users need to understand which sharpening stones work with which knife metals. This is why the field is one of continuous learning.

I once came across an interesting comment: A customer assumed that it didn't matter which 400-grit stone was used to repair a blade – the grit is the same for all stones. In principle, this is true; however, the actual grit can vary significantly between different manufacturers.

The major difference between different manufacturers' 400-grit stones lies in how well they bite into various metals. Basic, so-called European knife metals can be sharpened with nearly all stones, as can most carbon steels. However, when we start dealing with the toughest metals in the knife world, such as powdered steels, the differences between stones become very apparent. Examples of powdered steels include Elmax and S35VN, which are used in high-quality outdoor and folding knives.

A very thin-bladed chef's knife made from, for example, SG2 metal can be repaired with multiple stones. But when you want to change the angle on, say, a knife made of Elmax steel, you'll need to put in a lot more work, and the differences between stones will quickly become evident.

If you want a guaranteed reliable 400-grit stone, you should consider investing in the Naniwa Chocera Pro 400 stone.

Is a 400-grit stone coarse enough?

I often start sharpening completely dull or rounded blades with 180-220 grit stones. I also use them if the knife has visible marks, chips, or missing pieces. A 400-grit stone is sufficient for sharpening generally dull blades. However, if you want to minimize the number of stones at home, I would choose a 180-220 grit stone as the coarsest, then jump to an 800 grit stone, and from there to a 3000-4000 grit stone.

Which coarse stones does hiomakivi.fi recommend?

I use more different coarse stones than finer ones. I constantly strive to get a feel for which stone works best with each type of metal.

Here, I have picked my current favorites from grits 180-400.

TOP 4 Favorite Stones

Naniwa Chocera Pro 400 – The absolute number one in its field, a clinical performer. Works reliably with any metal.
Suehiro LD 180 – In my opinion, the absolute number one among grits 180-220. It bites well but requires a bit more practice to get the most out of the stone. Sufficiently large, thick, and durable.
Suehiro Debado 400-SNE (grit 320) – Perhaps my collection's least known coarse stone. Incredibly effective with an interesting feedback.
Imanishi WZ400 – Perhaps the most unique feel and user experience among coarse stones I have ever encountered, and this comment is meant in a very positive way.