Best Sharpening Stones

Buying guide for Best sharpening stones

All cutting edges – from pocket knives to axe-heads – benefit from regular sharpening. While there are a number of machines available, doing the job by hand is still a fast and efficient way to guarantee a sharp blade.

However, there are dozens of sharpening stones available, made of different materials of different grades, so it isn’t easy to work out which one you need. Luckily, we're here help you choose the right sharpening stone to care for your knives.

A sharp blade really is safer than a blunt one. A blunt blade tends to slide off whatever you're holding and can cut into your hand. A sharp blade slices easily – and precisely – into the object.

Sharpening vs. honing

Is there a difference? Many people confuse the two tasks, but yes, there’s a difference. Which one you need to do will determine the sharpening stone you buy.

Sharpening is putting a keen edge on a knife or cutting tool that has become blunt through use. It also applies to repairing a damaged edge. Sharpening is creating the edge when a blade won’t cut.

Honing is the regular maintenance that keeps a sharp edge sharp. It’s a process that may only take a few seconds and is carried out regularly to keep the tool sharp in daily use. Many chefs, for example, use a “steel” to hone their knives each time they use them. At the other end of the spectrum, fastidious craftspeople can spend hours honing and polishing an ultra-fine edge on a knife, chisel, or sword.

Choosing a sharpening stone

Two factors define your choice of sharpening stone: grit and material. And the type of sharpening you do most often will determine whether you need a bench, pocket, or combination sharpening stone.

Grit

The grit number tells you how coarse or fine a sharpening stone is. Normally, this ranges from 400 to 8,000, though finer specialist stones are available. You might also see them described as coarse, medium, fine, or extra fine, which is less helpful.

• Coarse: 400 to 500 grit is considered “coarse.” It’s used for initial sharpening of a very dull blade and bringing a nicked blade back into shape. It's also what you might use on a spade or lawnmower blades.

• Medium: 1,000 to 3,000 grit denotes a general-purpose or “medium” sharpening stone. It will give a keen but not razor-sharp edge that's acceptable for many household and outdoor uses.

• Fine: 4,000 grit and higher is a “fine” sharpening stone (sometimes called a finishing stone). This is for when you need that particularly sharp edge, on carving tools for example. These are the grits used for honing.

Diamond sharpening stones might use the same rating system, but they often do not. Sometimes you’ll see a particle size in microns. One micron equals one thousandth of a millimeter. The smaller the number, the finer the grit. The following is an approximate comparison:

• 400 grit: 45 microns

• 800 grit: 25 microns

• 2,000 grit: 10 microns

Material

Factors other than grit affect how well sharpening stones work, so we need to look at the material, too.

Oilstones: Many people will recognize a carborundum stone (silicon carbide). These relatively soft materials have been a feature in homes and workshops for centuries. Your father or grandfather might have had one. There are three kinds of oilstone commonly available: silicon carbide stones, Arkansas stones (made of novaculite, traditionally mined in Arkansas), and aluminum oxide (also called India stones). All of these stones require oil as a lubricant to help the cutting process. Some can use water, but it's important to check.

• Pros:

  • Inexpensive

  • If you're looking for a cheap sharpening stone for general-purpose use, an oilstone provides a perfectly adequate low-cost solution.
     

• Cons:

  • The surface can become smooth – glazed – as slurry and small particles fill in the grit.

  • These stones often get worn out of shape. Usually a shallow groove forms in the middle because that area gets more use than the edges. Experts recommend a number of ways to restore surface and flatness, including cleaning with kerosene or rubbing on a sheet of sandpaper.

Waterstones: Like oilstones, waterstones can be made from aluminum oxide or silicon carbide. There's also a highly prized natural material called siliciclastic, mined in Japan, that can produce extremely fine sharpening stones. Most waterstones use the same materials as oilstones, but the binder that holds them together is different. These stones use water as a lubricant. Waterstones must be soaked before use, but it only takes ten minutes.

• Pros:

  • The surface breaks up quickly, so new cutting edges are revealed.

  • Sharpening is much quicker than with oilstones.

  • These do not glaze.

  • These are easier to restore if they go out of shape.

  • If you're looking for a cheap sharpening stone for general-purpose use, a waterstone provides a perfectly adequate low-cost solution.

  • If developing the perfect cutting edge is your goal, a Japanese waterstone will probably be your preference.

• Cons:

  • Waterstones are soft, so they wear and go out of shape more quickly.

  • Fine Japanese waterstones are very expensive.

Ceramic sharpening stones: Ceramic sharpening stones are made by combining aluminum oxide and ceramic powders in a process called sintering – heating and compressing the materials until they bind together.

• Pros:

  • Ceramic stones don’t need lubricant, so these are particularly useful in situations where using oil or water would be difficult or inconvenient.

  • These are harder wearing than oilstones or waterstones.

  • If developing the perfect cutting edge is your goal, a fine-grit ceramic will probably be your preference.

• Cons:

  • Ceramic stones are difficult to repair if damaged.

  • These are usually more expensive than oilstones or waterstones, particularly the finer grits.

Diamond sharpening stones: You might expect the hardest natural substance to make good sharpening stones, and it does if you choose carefully. These stones are made with industrial-grade diamond particles, which are fixed to either a metal or plastic sheet using special adhesives. With lots of very hard, very sharp edges, they usually require much less effort than other sharpening stones. Although water is often recommended as a lubricant, you don't need it, giving these stones added versatility.

• Pros:

  • Diamond stones are durable.

  • These stones are versatile.

  • Diamond stones don't glaze or get out of shape.

  • Some diamond sharpening stones are perforated to help clear dust and debris.

  • Some stones are solid sheets to prevent knife or tool edges catching in the holes.

  • These stones are excellent for general-purpose sharpening. If you've got a few dollars more, good-quality diamond stones are the best all-round sharpening method.

• Cons:

  • The diamond particles can be very small or widely spaced, leading to an inferior product.

  • Fine-grit diamond stones are uncommon and expensive, so these aren’t the best choice for honing.

Bench, pocket, or combination stones

Bench: If you're going to be sharpening a variety of items from pocket knives to garden shears, you'll want a good-sized bench stone. Common sizes of eight-inch and ten-inch will give you the surface area you need, as well as good stability. A stand is nice, as is a protective box for when you aren’t using it.

Pocket: Pocket sharpening stones can be small versions of bench stones or have handles. If you need something very portable, there's a huge variety.

Combination: Both bench and pocket sharpening stones are often double-sided combinations, giving you a coarse or medium grit on one side and a medium or fine grit on the other. This is often more economical than buying separate stones, and it saves space. Specialists usually go for individual stones, and many design their own sharpening “station.” If precision is important to you, you can find several ideas for these online.

Sharpening stones prices

You can expect to pay from $15 to $650 for a sharpening stone, depending on material and grit.

Inexpensive

You can find a perfectly acceptable double-grit oilstone that will keep all your kitchen and outdoor knives in good condition for about $15. Between $15 and about $25, you'll find all manner of portable or folding sharpening stones that are ideal for camping trips or keeping in a drawer in your RV.

Mid-range

High-quality oilstones and waterstones have similar prices. Silicon carbide versions run from around $20 to $65. The same for India stones. Combination Arkansas stones can cost $50 to $100. Diamond stones are often thought of as the more expensive choice, and you can pay $70 or more for one. Bear in mind how long they last. They often work out to be very economical in the long run. However, beware of cheap diamond sharpening sets (often sold in packs of three different grades). They might look like a great value, but you'll struggle to find many diamonds in there! If it looks too good to be true, it is.

Expensive

For the perfectionist, there's nothing to match the fine grits offered by Japanese waterstones and ceramics. There's nothing like the price either. A 30,000-grit honing stone (also called a lapping stone) is perhaps the pinnacle of the sharpening art, but it will set you back between $350 and $650.

Tips

• Be patient. Learning to sharpen properly takes time. There are some excellent videos online that demonstrate technique. The important thing is not to rush. If you do, you'll tend to rock the blade, which does more harm than good. Smooth, even strokes allow you to maintain the correct angle.
• Get the angle right. One of the main factors in sharpening any kind of cutting tool is getting the angle right. For most household knives that's around 20° or 21°. Manufacturers of Japanese chef’s knives recommend 17°. Bench plane blades should be sharpened at 30°. Always check.
• Use the right sharpening tool for the job. You'll get the job done more quickly and get a better result. The sharpening stones we've discussed are great for all kinds of flat blades, but cutting edges come in many different shapes. Fortunately, there are specialist sharpening devices for serrated blades, woodworking gouges, pruning shears, and chainsaws.
• Clean and dry your sharpening stone before putting it away. It can be as easy as a quick wipe, and it seldom takes more than a minute or two. If you don't clean your stone, any residue can eat into the surface.

Most sharpening stones benefit from a lubricant, but it's vital that you use the correct one. Some oils will destroy the structure of a waterstone.

FAQ

Q. Can I sharpen ceramic knives?

A. Ceramic knives should stay sharp a lot longer than steel knives. The ceramic material is extremely hard – very nearly as hard as diamonds – which makes them very difficult to sharpen. These knives can wear away the surface of even a diamond sharpening stone. If you do need to sharpen a ceramic knife, we recommend you contact the manufacturer. Most offer to do it for you if you send back the knife.

Q. Should I use water with a diamond sharpening stone?

A. A diamond sharpening stone can be used with or without water, but tests show that using water enables you to sharpen your blade more quickly. It's also easier to clean up afterward – a wipe with a dry cloth. Using a dry diamond stone leaves a powdery residue that is difficult to get rid of. Note that you should never use oil on a diamond stone.

Q. Is a leather strop better for honing than a fine sharpening stone?

A. It's more a question of personal preference and the type of blade you're honing. Some people love using a leather strop for putting a fine edge on a blade. Barbers have done it with razor blades for more than a hundred years. But preparation can be a bit of a nuisance, and like all sharpening techniques, it takes time to master. Also, the natural “give” in leather isn’t suitable for chisels or heavy blades like machetes and cleavers.