Every collector needs two things: Knives and whetstones.
Knives we all know, obsess over and adore. Whetstones, on the other hand, remain a mystery to a large chunk of newcomers.
Yes, they keep your knives sharp… but what’s the difference between a whetstone and a water stone?
How do you read and determine the right grit size?
What is the proper sharpening technique?
What is the purpose of flattening a whetstone?
If you don’t know the answer to anyone of these questions, you’ve come to the right place. We’re going to look at these questions (and more!) in-depth, and give you all you need to know about whetstones.
What are Whetstones?
Whetstones, sharpening stones, water stones, oil stones.
What’s the difference between these? Is there any difference at all? Well, no. At least for whetstones and sharpening stones.
You see, the term “whet” means “to sharpen.” Therefore, “whetstone” is just another way of saying “sharpening stone.” Any sharpening stone you see, you can just as well call it a whetstone – they are the same thing.
Whet does not mean wet. Many people assume that whetstones need to be washed prior to use because of this name. While many whetstones do need liquid, there are also dry whetstones.
What about water stones and oil stones?
These refer to the type of liquid needed to lubricate the stone. A whetstone can be a water stone or an oil stone. Check out my article on the differences between these two here.
To Sum It Up:
Whetstone = Sharpening Stone
Water Stone and Oil Stone = Types of Whetstones
Aside from that, there are other differences between whetstones. These are the material they use and their grit size.
What are Whetstones Made of?
Ever since knives were invented, people have used stones to keep them sharp. Back then, they didn’t have a lot of options – they went with anything that could scratch their blades.
Nowadays, we have a plethora of great choices. You can choose between Arkansas stones, India stones, diamond stones, and dozens more.
There are two types of whetstones: natural and synthetic.
As you can probably guess, natural stones are found in nature.
They’re more difficult to “harvest”, they’re not as widespread as synthetic stones, they’re more expensive, and their grain can (sometimes) be inconsistent.
Yet they’re very popular.
What I love about natural stones though is their feel. There’s something about sharpening with a stone found in nature – not a manufactured one – that’s very appealing.
Novaculite is the most common material for these. It’s a colorful sedimentary rock that’s found in the mountains of Arkansas – which is where we get Arkansas stones.
You may have also heard of Belgian coticules (known for its spessartine) or Belgian blue (limestone) whetstones. These two are highly-popular Ardenne stones that are known for their beauty and fine grit (more on grit soon). Unfortunately, these stones are not as abundant as they used to be.
Then there are the Japanese whetstones.
There’s something mystical surrounding Japanese knives – which carries to their sharpening stones as well.
Because of the country’s geology, they have a very special type of stone. It’s a sedimentary rock similar to novaculite, only it is softer and clay-like.
This rock is used to create some of the finest grit whetstones on earth. These are the stones that the Samurai would use to keep their katanas razor-sharp.
The word “synthetic” often stirs up images of plastics and fakes in people’s minds. When it comes to whetstones, however, this only means “man-made.”
The materials used to make synthetic whetstones are also found in nature. The only difference is that they need to be manufactured first.
Silicon carbide and aluminum oxide are the most common materials used for synthetic whetstones.
Both of these materials can get really hard – a lot harder than natural stones. They grind steel fast and can give even the dullest blade an edge – especially silicon carbide.
Synthetic stones are always consistent. Since they’re man-made, you can expect even grains all throughout.
Plus, they’re a lot cheaper. Synthetics don’t have the appeal of natural stones, but if you’re talking performance and practicality, they are way better.
Another type of synthetic whetstone is the diamond stone.
Aren’t diamonds natural?
Well, yes, but not these ones.
Diamond stones are made from manufactured diamonds. Small diamond crystals are placed on a flat metal plate for the ultimate hardness. You won’t find a whetstone that can sharpen as fast as these.
These stones are the most expensive type you can get. That said, they also last the longest. Since nothing is harder than diamonds, you’ll almost never have to flatten your stone (more on flattening soon!).
What are Whetstone Grit Sizes?
Knowing the material of your whetstone is important. But it’s even more important to know its grit size.
You’ve probably heard of 320-grit stones, 1,000-grit stones, or maybe even 12,000-grit stones. What do these all mean?
Grit size is a measurement of how coarse or fine your whetstone is. The higher the grit size, the finer the whetstone – the less harsh it will be on your blade.
What do I mean by harsh?
Let’s say you have a dull blade. A blade that, even if you tried to cut yourself, it wouldn’t get through your skin. You’d need a harsh sharpener to give this knife an edge.
Pick a low-grit size, and it’ll scrape off steel fast. After a few strokes, you’ll find it significantly sharper – sharp enough to hurt you.
Now let’s say you have a sushi knife. It is already very sharp, but you know it’s not enough to slice sushi without bruising it.
In this scenario, you’d need a high-grit stone. A low-grit will eat way too much steel and can damage the blade. A high-grit, on the other hand, will take this knife from sharp to razor-sharp.
How to Choose Grit Size
The higher the grit, the softer the stone… but how do you know which one you need?
To help you with this, you can imagine grit sizes in three categories: low, medium, and high.
In the low category are the hardest of the hard stones. These are the stones with grit sizes from 0 to 320.
If an edge needs a lot of work, these are the stones you need. They can fix super dull blades, chips, cracks, and other problems.
Here you find stones made from silicon carbide, diamond stones, and any other hard material.
When finished, these stones leave a rough edge. Because they’re so hard, they can only go so far in the way of sharpness. For a sharper edge, you’ll need a medium stone.
Medium stones aren’t the best for fixing blades. They can sharpen an ultra-dull or damaged edge, but it’ll take a lot of time for them to do this.
Instead, these stones, which range from about 400 to 2,000 grit size, are used for the main sharpening. They take rough edges and turn them into smooth, sharp ones.
Here you find Arkansas stones, as well as some synthetic ones.
While they’re great for sharpening, these stones aren’t fine enough for polishing. Which brings us to the next level.
High whetstones, the finest of the fine. These stones are soft and delicate, but it’s through them that we get the most deadly edges.
This is where Japanese whetstones, Belgian blues, and some extra-fine synthetic stones come in.
Aside from giving your knives the sharpest edge, these stones also polish your blade. The shine they give makes your knife beautiful in the most deadly way.
Keep in mind though that most people don’t need an extra-high grit whetstone. I’m talking those in the 12,000-30,000 grit range.
Most non-professionals can’t tell the difference between a 5,000 grit and a 30,000 grit finish anyway. So don’t get carried away by those high numbers – as if your knives aren’t complete without them – and save some money instead.
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Now for the hard part.
The best whetstone in the world doesn’t sharpen your blade… you sharpen your blade.
What I mean is that even if you have the most expensive whetstone, you can’t sharpen a thing if you don’t know what you’re doing.
Proper technique is king when it comes to sharpening, not your whetstone.
The good news is that sharpening with whetstones isn’t difficult. There are several ways to do it, and I’ll show you my favorite method.
The bad news is that it takes practice. You’re not going to get it right the first time, but don’t get discouraged! Keep practicing until you master it – just like I have.
So, how is it done?
Step 1: Preparing the Whetstone
The last thing you want is a whetstone that isn’t stable. Not only will sharpening be unnecessarily difficult, but you could also round your blade.
Rubberized shelf liners or wet paper towels will do the trick. Once your whetstone is on top of these, it won’t go all over the place while you’re sharpening.
You also want to lubricate your stone. Depending on what type of stone you have, you’ll either use oil or water.
Some stones require you to soak them before using, while others you can simply splash and go. Check the instructions of your stone before using it. Trust me, you don’t want a clogged stone.
Step 2: Proper Hand Positioning
One thing I see too many people doing wrong is holding their knife wrong.
Sure, you can hold it any way you like – but don’t complain when your knife is unevenly sharpened.
For the best results, you need to use proper hand positioning.
Hold your knife firmly with your dominant hand (for this example, we’ll use our right hand. Flip everything around if you’re left-handed).
You want three fingers – your pinky, ring, and middle finger – wrapped around the handle. Your thumb should be on the spine of your blade. Finally, you want your pointer finger at the side, somewhere between the spine and edge (you’ll use this to add pressure while sharpening).
That is for sharpening the left side of your blade. When sharpening the right, your pointer stays on the spine while your thumb stays on the side.
With this grip, you can hold your knife steady and can sharpen at a consistent angle.
Your non-dominant hand won’t be idle either. Use it to add pressure while sharpening by placing two or three fingers along the body of the blade.
Step 3: The Right Angle
Now you need to find the right angle.
Not a 90-degree angle, but the correct angle for sharpening your blade.
Every blade is different. Most have an edge somewhere between 10-20 degrees, but there are so many exceptions.
Before sharpening any blade, it’s good to perform a little angle test first.
Take a sharpie and mark along the edge of your blade. Then run your knife against your whetstone, adjusting the angle until only the edge is hit (the sharpie marking makes it easy to see when you’ve accomplished this). It’s best to use a fine-grit stone for this – you don’t want to angle-test on a stone that will eat your steel fast!
Once you’ve found the right angle, you’re ready to sharpen.
Step 4: Sharpening the Left Side
Again, there are several methods to sharpen your knife. What I’ll teach you today is the push/pull method.
With your knife firmly in your hand and at the right angle, push and pull it against your whetstone. Use your non-dominant hand to press down on the blade when you are pulling.
DO NOT add pressure when you are pushing. When the edge of the knife is facing away from you, only add pressure when you pull.
On the flip side, when your knife is facing you, only add pressure when you push, never when you pull. This is to avoid your blade cutting into your whetstone – this damages both steel and stone.
If your blade has a belly, keep your wrist loose. You don’t have to sharpen in straight lines – this will flatten the curve of your belly.
As you sharpen back and forth, slowly move from the tip towards the base of your blade. Once you reach the base, you’ve completed one pass.
Step 5: Feeling for a Burr
How do you know you’re done?
You’ll feel a burr.
After a few passes, run your finger across the edge opposite the side you were working on. If you small “hairs” of steel, you know you’re done with that side.
If you sharpened at the right angle all throughout, you’ll feel this burr on the entire edge.
Step 6: Sharpening the Right Side
That is if your knife is double-beveled.
When working on the other side, don’t transfer the knife to your weaker hand. This will feel super awkward and may be dangerous. Instead, face the knife towards you and adjust your grip.
Then, repeat steps 1-4.
Step 7: Polishing Your Blade
Too many people think that after sharpening, their knife is good to go.
Failing to polish your blade is leaving the job half done. Yes, your knife will be better than before, but it can never achieve that razor-sharpness we all dream of without polishing.
To polish, you’ll need a strop. Stropping is the same as sharpening, the only difference is you should apply a lot less pressure.
Your knife will be shiny, burr-free, and deadly sharp when you’re finished.
Note: if you started with a damaged or extremely dull knife, you may want to sharpen with higher grits before stropping. Start with a low grit, move to medium, polish it with high, then finish it off with a strop. You can get any knife katana-sharp with this method.
Do Whetstones Wear Out?
As you sharpen your knife, your whetstone will inevitably lose material. A lot slower than your steel blade, but enough that after a few months of sharpening, your stone won’t be flat anymore.
Flatness is very important in whetstones. Running your knife is smooth and easy when the stone is flat. When it’s not, keeping the right sharpening angle will be very difficult.
That’s why you need to flatten your whetstones.
It’s essential to know how to flatten your stones. Every one of them will need flattening eventually. The harder stones may last longer, but they will lose their flatness at some point.
How is it done?
How to Flatten a Whetstone
The cheapest way to do this is to take your whetstone and rub it against the sidewalk outside. Rub it until it’s completely flat again.
You might think that’s a joke, but it actually is a feasible way to flatten your whetstone.
For a more “proper” approach, use sandpaper, a flattening stone, or a flattening plate. The technique is the same – rub it against your whetstone (or rub your whetstone against it) until it’s flat again.
If you’ve reached this far, you’re no longer part of that hypocritical bunch of people that say they love knives, but don’t know a thing about whetstones.
So go sharpen your knife…
…buy a new whetstone…
…or flatten your old one.
You now know all there is to know about whetstones.