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Explained: Do (Electric) Knife Sharpeners Ruin Knives?

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Knife sharpening is a maintenance task that is part of knife ownership, but it can be challenging if you are not familiar with sharpening knives and the tools and skills needed for the job. This is why we are always on the lookout for easier ways to keep our knives sharp. Can electric sharpeners fill this role, or do they ruin knives?

Electric sharpeners can damage and ruin knives. Electric sharpeners have limited edge angle options, may not be suitable for knives with specialized edges, and can ruin the temper on the edge. Poorly made electric sharpeners can also remove excessive amounts of material from the blade edge.

Electric knife sharpeners may seem like a fast and effective method to sharpen knives, but there are many anecdotes of these types of sharpeners damaging or even ruining knives. Electric knife sharpeners appeal to our need to sharpen knives faster, better, and with less effort or skill needed. Do these sharpeners deliver on their promise, or should you avoid them altogether?

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Do (Electric) Knife Sharpeners Ruin Knives?
Do (Electric) Knife Sharpeners Ruin Knives?

Are Knife Sharpeners Bad For Knives?

Electric sharpeners are a relatively new knife sharpening method, but you may have heard that they can damage or ruin knives. 

Electric devices have changed the way we do things in our modern world, from power tools in the workshop making jobs quicker and faster to appliances in the kitchen taking some of the grunt work out of mundane tasks. We have come to rely on and trust automated, electric tools to make tasks easier for us.

Why should knife sharpening be any different? Surely, a “power tool” for knife sharpening will make the task more efficient and a keener edge placed on the knife!

Unfortunately, the differences in knives, steel, and purpose make it difficult to create a machine that will cater to every knife sharpening need in your home or kitchen.

If we take a general look at all knife sharpening methods, including electric knife sharpeners, they all work on the same principle at the basic level.

All knife sharpeners remove steel from the knife’s edge, which makes any knife sharpener potentially bad for knives. This is especially true if the sharpener is used incorrectly or the wrong sharpener is used on a particular type of knife.

There is no other way to sharpen a knife other than by removing steel from the knife’s edge to create a keen edge that will perform according to its intended purpose. 

Removing steel from the cutting edge is an unavoidable part of the knife sharpening process. So, how do we sharpen our knives without running the risk of ruining them altogether?

Do Knife Sharpeners Ruin Knives?

Do Knife Sharpeners Ruin Knives?
Do Knife Sharpeners Ruin Knives?

Knife sharpening is a skill that requires learning how to sharpen a knife and which sharpening method is best for each type of knife in your possession.

Knife sharpeners can ruin knives if the wrong knife sharpener is used to sharpen certain knives or if an incorrect technique is applied while sharpening. Using the right sharpener and the right method for each knife type will avoid damaging the edge and potentially ruining the knife.

There are several different methods for sharpening knives, but we will look at the two most common methods for knife sharpening: electric sharpening and manual sharpening. We will take a pragmatic look at these methods to guide you on their best application in your situation.

Do Electric Knife Sharpeners Ruin Knives

Do Electric Knife Sharpeners Ruin Knives
Do Electric Knife Sharpeners Ruin Knives

Electric knife sharpeners are intended to make the knife sharpening process easier and more convenient and limit the skill required to get your knife sharp.

However, there are some problems associated with electric knife sharpeners that could cause serious damage to the edge of certain knives and knife types that you should be aware of. 

Some of the ways that electric sharpeners can ruin a knife are as follows.

  • Incorrect sharpening angle.

Most electric knife sharpeners have preset angles that are used to sharpen the edge of the knife. Some models will have a selection of 3 or 4 angles for the edge bevel, limiting options.

Sharpening a knife with the wrong angle for the edge bevel can damage the knife, requiring more steel to be removed to repair the edge.

  • Edge geometry.

Not all electric sharpeners have the capability to sharpen single-bevel knives. Running a single bevel knife through an electric sharpener without this capability will ruin the edge. Likewise, many electric knife sharpeners cannot sharpen serrated-edged knives.

  • Damaging the temper of the steel.

Electric knife sharpeners can run very hot, heating up the steel on the edge of the knife. This heat can damage the temper of the steel on the edge of the knife, effectively ruining the knife.

  • Removal of too much material from the knife edge.

Electric sharpeners may be too aggressive with the action of the abrasive and the levels of abrasives. This can result in too much material being removed from the knife’s edge with each sharpening session. This can reduce the lifespan of the knife.

Does this mean that electric sharpeners do not have a place in your knife sharpening process? Electric knife sharpeners certainly can fulfill a role in your knife sharpening regimen but with caution.

Our recommendation would be to use an electric sharpener on cheaper knives in your kitchen, where standard bevel angles will be enough to sharpen the knife.

A manual knife sharpening method would be preferable for your more expensive or specialized knives, such as Japanese kitchen knives.

TIP: Have you ever thought if a knife can be too dull to sharpen? However many knife owners do not sharpen their knives once in a lifetime. Find out more about dull knives in the article below:
Can A Knife Be Too Dull To Sharpen? Here’s The Answer

Do Manual Knifes Sharpeners (Whetstones) Ruin Knives

Do Manual Knifes Sharpeners (Whetstones) Ruin Knives
Do Manual Knifes Sharpeners (Whetstones) Ruin Knives

Manual knife sharpeners, such as whetstones, have advantages over electric sharpeners, but some aspects of manual sharpening hold risks.

Manual sharpening offers more control and flexibility in the knife sharpening process but can potentially ruin a knife when performed by an inexperienced person. Incorrect sharpening angle, inability to maintain the angle, and poor technique can ruin the knife.

Manual knife sharpening is a skill that takes time, patience, and practice to master. Consequently, a novice knife sharpener can potentially ruin a knife on a whetstone.

However, in the hands of an experienced person, manual sharpening on whetstones produces a far superior finish on the knife’s edge than an electric sharpener.

It is worth the effort to acquire the skills necessary for whetstone sharpening, especially if you have expensive kitchen knives or specialized knives with single bevels.

To start learning manual sharpening skills, start on inexpensive knives until you have gained some experience before progressing to sharpening expensive knives.

If you don’t have the skills on a whetstone yet or are not interested in acquiring the skills, it would be best to outsource the sharpening of your expensive knives to a knife sharpening professional.

TIP: Some of the knife steels are not easy to sharpen. So what about popular elmax steel? Find out the answer in the article below:
Is Elmax Hard To Sharpen? All You Need To Know

Does Sharpening a Knife Damage It?

Does Sharpening a Knife Damage It?
Does Sharpening a Knife Damage It?

Sharpening is a necessary process for a knife to get a sharp, usable edge on the blade. The sharpening process removes steel from the blade, which will eventually wear it down until it is no longer useable. But this process can take years.

Sharpening a knife incorrectly can damage a knife, no matter the sharpening method used. Correct sharpening will give the knife a sharp, reliable edge, but it also removes steel from the edge of the knife, which shortens the usable life of the knife.

While sharpening a knife will eventually damage a knife, there is no way to get a sharp edge on the knife without outing it through the sharpening process.

Propper maintenance, such as regular honing of the edge, will reduce the frequency you need to sharpen your knives and extend their lifespan.

TIP: Are you looking to buy a new whetstone? Check out our recommendations (we personally use the first three ones):

Our PRO choice whetstones combo (Amazon links):

Our budget choice (Amazon link): Sharp Pebble Extra Large Sharpening Stone Set


Q: How Often Should I Sharpen My Kitchen Knives?

A: The frequency of sharpening your knives depends on usage. Regular users may need to sharpen every few months, while occasional cooks might sharpen annually. Always ensure your knives make clean, easy cuts to maintain kitchen safety and efficiency.

Q: Can Electric Knife Sharpeners Damage My Knives?

A: Yes, electric knife sharpeners can potentially damage knives if used improperly or on inappropriate knife types. Issues like incorrect sharpening angles, overheating, and excessive material removal can occur. Ensure to read the user manual and understand your knife type before using electric sharpeners.

Q: What is the Best Angle to Sharpen a Kitchen Knife?

A: Most western-style kitchen knives are sharpened at an angle of 20-25 degrees on each side. Japanese knives often have a sharper edge, sharpened to 15-20 degrees. Always refer to the knife manufacturer’s guidelines for the recommended sharpening angle.

Q: Can I Sharpen Serrated Knives Using an Electric Sharpener?

A: Some electric sharpeners are capable of sharpening serrated knives, while others are not. Always check the user manual of the electric sharpener and ensure it is suitable for serrated knives to prevent damaging them.

Q: Is Manual Sharpening Better Than Electric Sharpening?

A: Manual sharpening provides more control over the angle and pressure, often preferred for high-quality or specialized knives. Electric sharpeners offer convenience and speed, suitable for general-purpose knives. Both methods can be effective when used appropriately.

Q: How Do I Maintain My Knives Between Sharpening Sessions?

A: Use a honing rod regularly to realign the knife edge, ensuring it stays straight and efficient. Store your knives properly, either on a magnetic strip or in a knife block, and avoid placing them in a drawer where the edges can become damaged.

Q: What Safety Precautions Should I Take While Sharpening Knives?

A: Always secure the knife and sharpener to prevent slippage. When using a whetstone, maintain a consistent angle and use a sharpening guide if available. For electric sharpeners, ensure your hands and the cord are away from any wet surfaces to avoid electric shock.

Q: Can All Knives Be Sharpened at Home?

A: While many knives can be sharpened at home using electric or manual methods, some specialty knives, or particularly dull or damaged knives, may benefit from professional sharpening to restore their edge without risking damage.

Q: How Do I Choose the Right Electric Sharpener for My Knives?

A: Consider factors like the available sharpening angles, suitability for your knife types (e.g., serrated, straight edge), and user reviews. Ensure the sharpener is compatible with the knives you intend to sharpen to prevent accidental damage.

Q: Can Sharpening Wear Out My Knife Quickly?

A: All sharpening methods remove some material from the knife, gradually wearing it down. However, using the correct technique and not over-sharpening will ensure a long, useful life for your knives.


Electric sharpeners have their place in the home for sharpening knives, but they are best used on multi-purpose, lower-quality knives.

The reason for this is the lack of control over the sharpening process, limited edge bevel options, and the removal of too much steel. Overheating the steel on the edge of the knife and ruining the temper is also a possibility.

Expensive knives or specialty knives such as Japanese kitchen knives should always be sharpened manually on whetstones to put a quality edge on the knife.

TIP: Electric knife sharpeners have their place and can do a good job on certain knives, but they are not the appropriate choice for all knives. Find out more about the differences between electric and manual knife sharpeners in the article below:
Electric Vs. Manual Knife Sharpeners: 5 TIPS How To Choose