How To Use A Whetstone To Sharpen A Knife Or Sword

When you work with knives or swords, a dull blade makes cutting harder and increases the risk of accidents. This is why you want to keep your kitchen knives, hunting blades, and larger swords in prime working condition by sharpening them regularly.

While electric sharpeners can grind away too much metal and weaken the blade over time, a whetstone sharpens with accuracy while preserving the strength and integrity of your knife or sword. With this traditional method, you remove only what’s necessary, so you restore a blade’s edge and keep it razor-sharp for longer. In this guide, the team at Red Label Abrasives outlines how to use one for better performance, improved safety, and a longer-lasting edge.

Why a Whetstone Is A Popular Sharpening Tool  

A whetstone is a sharpening tool made from natural or synthetic abrasive materials. It works by gradually removing small amounts of metal, smoothing out imperfections, and reshaping the edge for better cutting performance. Whetstones come in different grit levels: coarse stones repair dull or damaged blades, while finer grits polish and refine the edge to razor sharpness. They can be used with water or oil to reduce friction and ensure even sharpening.

Unlike pull-through sharpeners or grinders, which can create uneven edges or excessive heat that alters the blade’s hardness, a whetstone gradually restores sharpness without compromising on durability. Because different blade types require different sharpening angles, a whetstone lets you tailor your technique to match whatever tool you’re working with.  

Choosing the Right Whetstone for Your Blade  

Not all whetstones are the same, and selecting the right one depends on the condition of your blade and the level of sharpness you want to achieve. For example:

• Coarse grit stones (typically ranging from 200 to 600) are best for dull or damaged blades because they remove metal quickly. 

• Medium grit stones (between 800 and 2000) are ideal for regular sharpening because they keep a blade sharp without excessive wear. 

• Fine grit stones ranging from 3000 to 8000 refine and polish the edge for a razor-sharp finish.  

Water Stones

Water stones, which are often made from aluminum oxide or natural materials like Novaculite, are preferred by most users because they cut metal faster and require minimal upkeep. These stones work by forming a slurry (a mixture of water and fine stone particles) that continuously exposes fresh abrasive material. Before use, they need to be soaked for about ten to fifteen minutes, though some modern water stones only require a quick splash of water to stay lubricated. 

In Japan, sword makers have long used water stones to sharpen katanas with a multi-step process involving progressively finer grits. However, the main drawback of using them is that they wear down more quickly than oil stones and require regular flattening with a lapping plate or coarse sandpaper to maintain an even surface.  

Oil Stones

Oil stones, which are traditionally made from materials like silicon carbide or aluminum oxide, use a thin layer of honing oil to reduce friction and prevent metal shavings from clogging the pores of the stone. Unlike water stones, they do not require soaking: just a few drops of oil before sharpening is enough to create the necessary lubrication. 

Oil stones tend to stay flat longer than water stones. However, they require more maintenance because once a stone has been used with oil, it cannot be switched to water, and cleaning the surface can be more difficult. 

Diamond Stones

For those working with exceptionally hard steels, such as high-carbon or stainless steel blades, diamond stones provide a strong alternative that doesn’t require soaking or oil. These stones, which are made with a metal plate coated in industrial-grade diamonds, remove metal quickly and stay flat indefinitely. However, diamond stones can be more aggressive than traditional whetstones, so they require a lighter touch to avoid over-sharpening or damaging the blade. 

Setting Up Your Whetstone for Sharpening  

Before sharpening, the whetstone must be properly prepared. 

• If using a water stone, submerge it in water for ten to fifteen minutes, then keep it wet throughout the process to prevent friction. 

• Oil stones should be lightly coated with honing oil before sharpening. 

Once the stone is ready, place it on a stable surface, such as a non-slip mat or damp towel, to prevent movement. Over time, whetstones wear down unevenly, so they should be flattened regularly using a lapping stone or coarse sandpaper. A level stone ensures better blade contact and a more consistent edge.  

Sharpening a Knife with a Whetstone  

The correct angle is key to getting a sharp, consistent edge. Most kitchen knives should be sharpened at an angle between fifteen and twenty degrees while hunting and survival knives typically require a twenty- to thirty-degree angle. If unsure, estimate the angle by holding the knife at ninety degrees, then tilting it halfway to forty-five degrees, and then tilting it halfway again.  

Once you’ve determined the right angle, take the following steps:

• Begin sharpening with the coarse side of the stone. Place the knife’s heel against the stone and apply light pressure as you move the blade forward in a sweeping motion, covering the entire edge from heel to tip. 

• Repeat this process ten to fifteen times on one side, then switch to the other. Keep the pressure consistent and maintain the same angle throughout. 

• Once the knife is sharp, switch to the finer grit side to polish and refine the edge. Use the same motion but with lighter pressure, repeating the process for eight to ten strokes on each side.  

Test the sharpness by slicing through a piece of paper. A properly sharpened knife should glide through cleanly without tearing or snagging. If necessary, continue refining the edge until the desired sharpness is achieved. To improve the edge further, use a honing rod or fine-grit stone to align the blade and support easier cutting.  

Sharpening a Sword with a Whetstone  

Sharpening a sword follows a similar process but requires some adjustments due to its size. Because swords are longer and heavier, securing them on a stable surface or using clamps can help maintain control during sharpening. Rather than using short strokes, move the whetstone along the full length of the blade in long, even motions. This ensures an even edge without creating uneven pressure points.  

Maintaining a steady angle of twenty-five to thirty degrees is key to preventing inconsistencies in the edge. After completing ten to fifteen strokes on one side, flip the sword and repeat the process. Once the edge has been established, use a fine-grit stone to polish the surface and refine the cutting edge. To finish, strop the blade with leather to remove any remaining burrs and enhance sharpness.  

Common Sharpening Mistakes and How to Avoid Them  

One of the most common mistakes is applying too much pressure while sharpening. A whetstone is designed to do the work, and excessive force can remove too much metal, reducing the lifespan of the blade. Another mistake is failing to maintain a consistent angle, which results in an uneven edge that won’t cut properly. Practicing controlled, steady movements will help achieve a more precise result.  

Skipping the fine-grit stage is another common error. While a coarse stone removes dullness, it does not produce a truly sharp edge. Finishing with a finer grit ensures smooth cutting and a longer-lasting sharpness. Additionally, using a whetstone without proper lubrication can create too much friction, damaging the blade. Water stones should always be kept wet, and oil stones should be coated with honing oil before use. Finally, neglecting to flatten the whetstone can lead to uneven sharpening. Over time, stones develop low spots from repeated use, so flattening them regularly maintains their effectiveness.  

When to Use a Belt Sander Instead of a Whetstone 

While whetstones offer precision and control, there are times when a belt sander is the better choice for sharpening a knife or sword. 

Damaged Blades

Belt sanders are ideal for working with extremely dull, chipped, or heavily worn blades because they remove metal quickly and efficiently. If a blade has deep nicks or has lost its edge entirely, restoring it with a whetstone can take hours. A belt sander speeds up the process by rapidly grinding away imperfections and reshaping the edge in a fraction of the time.  

Longer Blades

Belt sanders are the preferred option for sharpening large blades such as swords, machetes, or cleavers. The length and power of a belt grinder allow for consistent, even sharpening across the entire edge, which can be difficult to achieve with a whetstone on longer blades. Knifemakers and professional sharpeners often use sharpening belts to establish a bevel before finishing the edge with finer abrasives or a whetstone for a razor-sharp finish.  

Another advantage of sanding belts is their versatility. Different grit levels can be used to achieve various sharpening results, from aggressive material removal with coarse grits to fine polishing with higher grits. However, because they remove metal so quickly, they do require a steady hand to avoid overheating or grinding away too much material. 

Troubleshooting Sharpening Issues  

• If a blade still feels dull after sharpening, the angle may be inconsistent or the edge may have developed a burr. Running the blade lightly across a fine stone or strop can remove any lingering burrs and improve sharpness. 

• If the whetstone wears unevenly, flattening it with a lapping tool will restore its surface for even sharpening. 

• Scratches on the blade after sharpening often indicate that a coarse grit was used too aggressively. Using a finer grit with lighter pressure can smooth out the surface and refine the finish.  

Keep Your Blades Sharp with Red Label Abrasives  

Sharpening a knife or sword with a whetstone takes patience and precision, but with the right tools, you can restore any blade to peak condition. It doesn’t matter whether you’re maintaining kitchen knives, hunting blades, or full-size swords: the right abrasive materials will help you get their edges in peak condition and keep them there.

At Red Label Abrasives, we are pleased to provide high-quality sharpening products, including premium sanding belts and abrasive kits designed for knife makers. If you’re looking for reliable sharpening solutions, check out our website for professional-grade abrasives that help you keep your blades sharp and ready for anything. For more information or to place an order, call 844-824-1956 or fill out our contact form today.