The 10 Best Sharpening Stones for Getting the Best Edge on Your Blades

The only way to keep your knives at their best is by regularly sharpening them. Keeping knives (and other blades) sharp is also the easiest way to help reduce the risk of blade-related accidents. Unless you are lucky enough to have a local sharpening service, then sharpening them yourself with a sharpening stone is one of the main ways keep your knives at their best.

There are three main types of sharpening stone or whetstone, and in this article, we give an overview of these, particularly focusing on the water stone and the oil stone. We also give you the lowdown on grits and why you may need to occasionally flatten a sharpening stone. We also review a number of bestselling sharpening stones to help you to find the best sharpening stone for your blade requirements.

Things to Consider Before Buying A Sharpening Stone

Sharpening stones, whetstones or water stones sharpen straight steel knife and tool edges by grinding and honing. Sharpening stones are split into different types, with the most common types being water stones and oil stones. Diamond stones are also used for some types of sharpening.

Most manufacturers provide guidance on how to use their sharpening stone and although sharpening is a skill that takes time to acquire, being able to sharpen your kitchen knives and other tools such as pocket knives, axes and chisels makes it a skill well worth developing.

When choosing a whetstone, a 6" stone is usually adequate for sharpening kitchen knives, but if you do want to sharpen larger tools, then a larger whetstone will be easier to work with.

The Water Stone 

Water stones are available as natural and synthetic stones. Japanese water stones are natural stones often used as a honing stone or for polishing with. A harder stone, often preferred by sharpeners who are more experienced, a Japanese water stone can give a mirror finish to the blade edge. A Japanese water stone also carries a premium price tag, especially as many of the mines where the stones were sourced are now closed.

If you are looking to buy a Japanese stone, then an arato or coarse stone will have a 2300 to 800 grit, a nakato or middle stone can be from around 800 to 15000 and a shiageto or finishing stone will be around 1500 upwards.

A synthetic water stone is usually made from aluminum oxide, the same material as India stones. Water stones are softer than India stones as the binder which holds the abrasive (aluminum oxide) in the stone breaks away easier to then be replaced with fresh and sharper material. This means that sharpening on a water stone is faster however, this softness also means that it will wear down faster and because it often wears down unevenly, it will need flattening to bring it back into shape.

Synthetic water stones can be available in grit grades from a 100 to 10,000 grit, although a higher grit may not always be as fine as it should be, generally, the lower the grit, the more accurate the sizing will be. The lower the grit grade, the coarser the stone, which means that more metal will be removed from the edge of the blade.

Synthetic water stones can be especially useful when sharpening stainless steel Western-style blades. Synthetic stones usually always need soaking in water before use and keeping moist throughout sharpening.

The Oil Stone and Honing Oil

Oil stones cut slower than water stones and because oil is used for cutting with it also means there is more mess cleaning up the swarf (metal chips).

The oil stone is the type of stone that most of us are familiar with; a natural oil stone is also known as an Arkansas or novaculite stone. Novaculite stone is quarried in Arkansas and the grades of the stone usually range from around 500 to 6000 grit, although like other natural whetstones, these are not measured to an exact grit, as there is also natural variation.

Instead, they are known as soft Arkansas (finer grit), hard Arkansas, hard black Arkansas and hard translucent Arkansas. The last two of these are rarer stones and will therefore cost more to buy. There is also a washita grit which is rarely used as it is a very soft stone.

The advantage of grit variation in Arkansas and other natural sharpening stones is that this creates various micro-serrations in the blade edge which means that the blade will wear down at different rates – keeping the edge for longer.

Arkansas stones are extremely hard and will rarely need flattening although they can take longer to sharpen with. If you want a mirror finish you will find this harder to achieve with an Arkansas stone. Some people may use water to sharpen with an Arkansas stone rather than oil. If you want to try water, then do so before you use oil; as once oil has been used, you will not be able to use the stone with water.

Applying oil to an oil stone not only carries away the waste coming off the blade edge, it also helps keep the blade angle consistent and reduces the heat that is produced by friction. This heat can slightly warp a blade, and although to some extent water can reduce friction, oil is much better at reducing the heat.

Honing oils usually contain highly-refined mineral oil, a light oil that will not harden or turn rancid. Mineral oil is also odor-free and will not release any fumes. Honing oil may also contain other additives such as detergents.

When applying oil to an oil stone, it should be rubbed in rather than just pouring over and if you do not have honing oil to hand, then other light oils can be used. It needs to be a light oil as a heavier or viscous oil will prevent the stone from sharpening properly.

Oils such as vegetable oils should not be used as these will harden and clog the stone - stopping it from working properly. These types of oils can also turn rancid or give an ‘off’ smell over time.

Synthetic oil stones can be made from aluminum oxide or silicon carbide. The India stone is a synthetic oil stone which is able to cut fast and develop a fine edge on tools and knives.

India stones are usually orange or brown colored and they tend to be graded as fine, medium and coarse. Silicon carbide stones are also graded in this way. Usually gray colored, these are also fast cutting stones but as silicon carbide stones struggle to produce a fine edge, they are best used as a general coarse sharpener. You can then use a finer stone for finishing/honing with.

The Diamond Stone

Made from small industrial diamonds which are usually attached to a metal plate, diamond stones do not need flattening and have a long lifespan. However, these are aggressive stones which will wear down an edge if you are not careful and as coarse grit stones, they cannot hone or finish a blade.

Grits and Gradings

Like sandpapers, whetstones are usually graded by their grit. A grit of less than 1000 is a coarse grit stone suitable for removing chipped edges or nicks in a blade. It can also undertake rough sharpening, such as when your knife has completely lost its edge. A coarser stone like this should not be used too often as it will eventually wear your knife down.

A whetstone of 1000 to 3000 grit will sharpen ‘normally’, such as a knife that has dulled with use. Grit graded at 2000 or above will take off any fine scratches and burr left by a coarser stone, while 4,000 upwards will hone/finish a sharp blade edge and give a mirror finish.

A number of experts suggest that a stone graded above 10,000 will not make any measurable improvement to an edge.

If you are new to sharpening, then a dual sided 400/1000 whetstone is ideal to start with as this will allow you to repair any minor chips and assess sharpening as you proceed, while not scratching the knife.

Maintaining a Sharpening Stone

A sharpening stone’s lifespan can be lengthened by always using it on a level surface, avoiding sharpening bulkier tools on a softer stone, sharpening the blade at the correct angle and using all parts of the stone.

Cleaning the stone after use is also important. Usually just washing a water stone will clean it after use, but if it is particularly dirty, then you can spray some WD-40 on it then rub steel wool over it in circles. This will usually bring up most of the dirt. The stone can then be washed thoroughly under running water to remove the remaining WD-40. As WD-40 is kerosene-based rather than oil-based, it makes suitable for cleaning water or oil stones with.

Over time, a whetstone will start to dip, often in the middle. A small dip may not always cause issues with sharpening, but when sharpening some types of knives, or tools such as chisels, on a stone with a dip will cause problems.

A water stone which is dished is one which is taking on an uneven surface; often because certain parts of the whetstone have been used more often than other parts.

To straighten out a dished whetstone, or remove a dip from it, you will need to flatten it. If you can lay an engineer’s square or straight edge across your stone and see a gap between the square and the stone, then it needs flattening.

If you hear someone refer to a ‘loaded up whetstone’, this means the stone is loaded up with metal chips and other bits. This can also be removed by flattening and making sure your knife and hands are clean before you begin sharpening can help prevent loading up in the first place.

To flatten a whetstone, you will need a flat, coarse stone called a flattening stone or lapping plate. Flattening is quite easy to do. You will need to mark your whetstone with pencil lines and then under running water, or with both stones wet, run the water stone over the lapping plate in a circular motion to cover the full surface of the stone. As you do this, the pencil marks will start to disappear from the whetstone. Once the pencil lines are gone, the stone is now lapped.

You can then use the engineer’s square again (or similar) to check that the gap between the square and water stone has now disappeared.

If you do not want to buy a flattening stone, then a 100 grit wet-dry sandpaper can also help flatten a stone. You can then use a 400 grit paper to remove any scratches caused by the wet-dry from the surface of the stone.

After using a whetstone, it should always be left to dry out for a couple of days before putting it away. If it is still damp when you put it away it may develop mold and can decrease in quality.

Conclusion

In this article we have looked at the difference between natural and synthetic stones, as well as the pros and cons of oil, water and diamond stones and what grit gradings actually mean when sharpening. We have also offered a number of tips to help you get the most from your stone, including how to flatten it when it develops a dip.

We hope that you have found our article on sharpening stones useful; whether you are a sharpening novice or seasoned pro. We also hope that our reviews of ten of the best sharpening stones has been useful and that you now feel comfortable selecting the right stone for your kitchen and household blades.