Sharpening stones come in various options; two of the most popular are the whetstone and the diamond stone. There are distinct differences between them, primarily around how they are made, the materials they are made from, and the type of blades used to sharpen.
Diamond stones have tiny diamond particles glued to the metal surface and don’t need a lubricant but will last much longer. At the same time, whetstones are made from natural stone, require oil or water as a lubricant during sharpening, and will eventually wear out.
Understanding the critical differences between these two types of sharpening stones based on your specific needs will help you choose whether you opt for the whetstone or diamond stone to keep your blades sharp for life.
Whetstone Vs. Diamond Stone – The Diamond Stone
Let’s start by looking at the diamond stones in more detail, and we will consider how they are made, what they are made from, and the practical pros and cons of these highly durable sharpening tools.
How Are Diamond Stones Made
There are three primary ways that diamond stones are made. The first method utilizes a block of machined steel or aluminum upon which the diamond chips are integrated. While this produces the flattest surfaces, the cost of materials and manufacture is very high, so this is not a standard option for diamond stone production.
The second way involves impregnating diamond chips into a thin steel plate which is then glued to an aluminum block. The method used to cut the steel is essential as high-temperature laser cutters can deform the steel plate, resulting in more machining needed to correct the deformation.
This is often done using high-pressure presses to straighten the plates. In most cases, more straightforward steel-cutting methods offset costs and time in the manufacturing process.
This is the most common method used to produce diamond stones.
The third way involves using flexible copper or plastic sheets impregnated with diamond chips and then glued to various backings depending on the customer’s requirements. One of the drawbacks of these flexible foils is that they can be easily damaged or cut when sharpening.
Whetstone Vs. Diamond Stone – Advantages Of Diamond Stones
Diamond stones offer the user a great many advantages. While they are often more expensive than whetstones, one of their most apparent advantages is that they will outlast whetstones by some margin as they are tough and not quickly dulled or damaged.
Diamond stones are also excellent for people who need to sharpen tools and blades on the move as they remove the most material on each sharpening pass and sharpen faster and easier than the whetstones.
Diamond stones are great for hunters, outdoors people, and adventurers as they will not break or crack if dropped and can be used without oil or water to sharpen axes, hunting knives, and skinners to a sharp, practical edge.
While they don’t require lubrication when sharpening, most people will use a substance like WD-40 to make the sharpening process smoother. It is recommended that the surface be kept wet to extend the life of your diamond stones, especially when they reach medium sharpness.
Because diamonds are the hardest materials known on Earth, they can be used to sharpen materials that other types of stones cannot. For example, PM, HSS, and TC steels can be sharpened using a diamond stone, while whetstones would not even make a dent.
Unlike whetstones which will lose their shape and can develop distortions in the flat surface over time, diamond stones will retain their flatness regardless of the volume of use. They will suffer very little wear and tear over their lifetimes.
Do Diamond Stones Lose Their Sharpness
There is a common misconception that diamond stones remain sharp throughout their lifetimes, but this is not the case.
If you feel the surface of a diamond stone when new, it will feel sharp, but after a while, this sharpness will become dulled, and the diamond stone will move into a medium sharpness stage. In this sense, diamond stones are more like sandpaper than whetstones as they are essentially an abrasive surface on a non-abrasive base.
As with sandpaper, it will gradually remove less and less material over time as wear and tear on the diamond particles takes effect. This would be particularly pronounced when the stone is used to sharpen or grind tough materials.
However, you need to remember that while there will be some surface deterioration, it will take years to notice this. Using a whetstone for the same purposes would result in the stone getting damaged far quicker than a diamond stone.
One tip here is to buy a diamond stone that has monocrystalline diamonds, as these will maintain sharpness in the medium sharpness stage for much longer than polycrystalline diamond stones.
Monocrystalline diamond stones maintain their shape and offer higher sharpening speeds as they don’t lose shape and offer more consistent and accurate sharpening.
Whetstone Vs. Diamond Stone – Disadvantages Of The Diamond Stone
While there are not many drawbacks to using a diamond stone, there are a few that you should be aware of so that you don’t buy a diamond stone for a purpose for which it is not designed.
Firstly, if you need to impart a mirror finish to your blades, the diamond stones will not work.
A general issue with diamond stones is that they are not made in fine grit, usually, only medium grit at best, which means that very fine and precise sharpening cannot be accomplished using these stones.
Honing fine edges on blades would not be viable with a diamond stone. For general sharpening purposes and fast sharpening, the diamond stones are ideal, but whetstones are a much better choice when it comes to finer and sharper edges.
You can’t be overly aggressive with your sharpening when using diamond stones. Because they are so tough, you need to start slowly and check your edges periodically as you can remove too much materially with little effort.
Now that we have covered the diamond stones let’s look at the whetstones for comparison.
Whetstone Vs. Diamond Stone – The Types Of Whetstones
Firstly, many people may wonder about the name ‘whetstones.’ The term ‘whet’ means to sharpen and has no reference to ‘wetting’ the stone before using it.
Whetstones come in a variety of materials and options, and they are :
- Oil stones
- Arkansas Stones
- Water Stones
The Oil Stone
Oil stones are manufactured and utilize oil to remove the metal particles from the surface after sharpening. Oil stones are made from two materials: silica carbide and aluminum oxide.
Silica carbide stones are very fast cutting and come in coarser grits, so they are not ideal for more delicate edges.
The silica carbide stones have a MOHS Hardness rating of 9-10, and most people will start with this stone and then move to a finer grit stone to produce the sharpest edge.
Like silica carbide, aluminum oxide also has a MOHS hardness rating of 9, so this is another excellent option for the initial sharpening stage to remove material upfront. Unlike silica carbide stones, these oil stones have coarse, medium, and fine options, so you can achieve a complete range of sharpening with these oil stones.
Oil stones are not expensive and highly efficient, but like other stones, they will lose their flatness over time and either need to be reflattened or replaced.
The Arkansas Whetstone
Perhaps one of the most famous stones of all, the Arkansas stones are sought after and used by knifemakers and regular folks alike to keep beautiful edges on their knives.
These versatile stones can be used with oil or water and are commonly known as Novaculiate, a Latin term meaning ‘razor stone.’
This type of stone has been used since the 1800s amd is quarried from the Ouachita Mountains in Arkansas and then shaped into the various stones found today.
Arkansas stones are classified into four different categories based on their coarseness:
- The Soft Arkansas Stone – This is the coarsest of all the four and typically is rated between 400-600 grit and is marbled in color with variations in orange, pink, gray, black, and white. These would be used for the initial sharpening before moving to the finer grits.
- The Hard Arkansas Stone – This is a fine stone equivalent to 800-1000 grit and can have some orange or reddish coloring, but they are primarily off-white in color. This would be used after the soft stone in the sharpening process.
- The Black Arkansas Stone – This is an ultra-fine stone with a 2000 grit rating and typically is blue-black or black in color. This stone is exceptional at producing ultra-fine edges after using the coarser hard stone.
- The Translucent Arkansas Stone – This is the very finest stone in the range and would be equivalent to a 3500-4000 grit, and while usually light gray or white, some may have shades of pink.
The range of Arkansas stones provides a complete set of grit ratings to deliver super sharp and fine edges. While they too will suffer some loss of their flat surface over time, when looked after and used correctly, they can last a very long time, even with extensive usage.
Waterstones are named as they require water to be used for lubrication during sharpening. These stones can be artificial or natural; Waterstones from Belgium and Japan have been used for centuries.
Belgian whetstones have been exported since the 17th century and emerged during the time of the Roman occupation, and these are generally finer stones with grits ranging from 4000 to 8000.
Japanese Waterstones are still in demand today and are particularly popular with knife owners and straight razor users worldwide.
Although the quarrying of these stones has made them rare, they are still mined from quarries outside Kyoto.
These stones have a wide grit range between 500-10000.
Synthetic Water Stones
These artificially produced stones offer one of the fastest sharpening options making them popular with chefs and woodworkers. While not as fast as the diamond stones, they are faster than Arkansas or Waterstones.
The grit range on these stones is between 120 and 30 000, so they have excellent versatility for various applications.
Whetstone Vs. Diamond Stone – Which Should You Choose
Choosing a sharpening stone gives you multiple options in terms of coarseness and price. Most stones start from around $20 and can run as high as $500 or more for Japanese whetstones, but the choice ultimately comes down to the type of sharpening you need to be done.
If you are a knifemaker or bladesmith, you would probably opt for the Arkansas stones and have a Waterstone in fine grit to finish and polish off edges, while more rugged usage would require diamond stones.
If you are starting with sharpening or making knives, having a good quality set of stones that offers a variety of coarseness is ideal. Still, you can mix and match with oil, Waterstones, and Arkansas stones and have a diamond or two.
There are no hard and fast rules around which type of stone to have in your armory, and as you develop your skills, you may gravitate toward specific kinds of stones and grits that are more suited to your particular craft.
Whetstone Vs. Diamond Stone – Know Your Steel
Remember, though diamond stones offer faster cutting, they don’t offer the finer edge options that many precision blade makers would require, but that doesn’t mean they don’t have a place.
A good quality diamond stone used for the ‘grunt work’ is a good investment, and if you have stainless steel blades, then diamond stones are particularly effective.
Using Waterstones or Arkansas stones to create the more detailed edges and mirror finishes that only those stones can produce would be effective on softer steel blades, so you need to be clear about the type of steel you have or that you would prefer if you are making them.
Knowing what steel you will be working with or the knives you have will impact the type of stone you choose, so do some research into the best stone options for your blades.
Diamond stones for longevity, durability and speed , whetstones for cutting edge sharpness and superior quality finishes bring the best of both worlds.
Choosing a whetstone or diamond stone will greatly depend on how you intend to use them; each has its place in your workshop or pocket. Whether outdoor adventures beckon or fine-crafting razor-sharp edges for combat use or general carry, good sharpening stones are a worthwhile investment.