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Sharpening knives is a necessary part of owning a knife and is a maintenance task that we all need to perform to keep our knives in peak operating condition. Whichever method you choose to sharpen your knife it will involve passing the knife over the gritty surface of the sharpener. What does this do to the knife? Does sharpening a knife remove metal from it?
When sharpening a knife, the edge is passed over an abrasive that grinds metal off the edge of the knife to reshape and refine the edge back to a fine, sharp edge. All knife sharpening methods will remove metal from the knife, which is why sharpening should only be done when absolutely necessary.
Sharpening a knife requires the steel to be brought to a fine edge which equates to sharpness. The process of sharpening will slowly remove excess mass from the steel and shape the edge of the blade to the physical dimensions that will make the edge of the knife sharp. Does the sharpening process remove a lot of material or metal from the knife?
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How Does Sharpening A Knife Remove Metal?
Sharpening a knife is essentially aggressively removing metal from the edge of a knife with an abrasive material. There are different levels of aggression required when sharpening, depending on the state of the edge of the knife that needs sharpening.
A very dull knife would need more aggressive sharpening, which would remove more material. The coarse or rough surface of the knife sharpener is an abrasive that grinds particles of the metal from the edge of the blade to reshape the edge to the correct profile for a sharp edge.
This grinding process wears away steel in an even fashion from the edge of the knife to make sure the edge is consistent along the entire length of the knife.
When a knife is very dull, the edge often has to be removed completely by the sharpening process and re-established. This is achieved by an aggressive sharpening at the beginning of the process.
The level of aggression in the sharpening is achieved by using a coarse grit sharpener which removes the most steel from the edge and will remove the old edge and begin reshaping a new edge.
Moving to less aggressive abrasives will further refine and shape the edge of the knife to the correct thickness and begin to make the edge smooth, removing the rough surface from the previous, coarse grits.
Less Aggressive Sharpening
A knife that is not extremely dull would only need a touch-up sharpening session, in which case you would use less aggressive abrasives.
You would not start sharpening this knife with a coarse grit sharpener; you could start with a medium grit or fine grit, depending on the state of the edge. These finer grits of sharpening surfaces will remove less material from the knife edge, but there will still be some loss of material.
Any form of sharpening will always remove metal from a knife. The more aggressive the sharpening, the more material will be removed. This is one of the reasons that frequent sharpening of a knife should be avoided.
Does Honing Remove Material From A Knife?
Honing is not the same process as sharpening a knife. A frequent mistake that many knife owners make is to sharpen a knife when all they should be doing is honing the knife.
To understand the different actions between honing and sharpening procedures, you have to understand what happens to the edge of the knife when it becomes dull. A sharp knife has a very thin cutting edge on the blade. This thin edge is flexible due to its thinness.
Sometimes the thin edge gets folded over to one side or other during the use of the knife. This will cause the knife to feel dull to you in that it has lost some of its cutting capability.
A knife in this state does not need sharpening. It needs honing, which does not remove material but rather re-aligns the rolled-over edge and restores the knife to be a sharp, usable tool.
Some honing processes such as using a rouge, which is a fine abrasive, on a leather strop will remove tiny amounts of metal from the edge and smooth and polish the edge to be almost a mirror finish.
This aids in making a sharp knife an ultra-sharp knife but still removes small amounts of metal.
Honing a knife should be done more often than sharpening, and the more often you hone the edge of the blade, the less frequently it will need sharpening.
Depending on the frequency with which you use your knives, they may need honing before or after every use, depending on what the knife is used for.
As a knife owner, you should own a good honing tool such as honing steel or a leather strop so that you can easily run the blade over it to re-align the edge when you need to.
TIP: Knife sharpening and honing is often one of the aspects of knife making and knife maintenance that many knife makers struggle within the beginning. Do you know what comes first? Find out the answer in the article below:
Sharpen Or Hone A Knife: What Comes First?
Does Sharpening Wear Down Your Knife?
Since the process of sharpening removes metal from the blade of the knife, sharpening does wear the knife down.
It is for this reason that honing frequently is recommended to limit the actual sharpening that you do on the knife. Frequent sharpening will wear the edge of the knife away and will quickly make the knife unusable for its intended process.
If you hone your knife regularly, you should only need to sharpen the knife every 8 weeks or so if the knife has heavy use.
With a knife that is not used every day, you could push the sharpening out to one every six months, as long as your keep up with the honing.
What Happens If You don’t Sharpen Your Knife?
This does not mean that you should avoid sharpening your knife when it needs attention. Not sharpening a knife when it is necessary could almost be as bad as sharpening it too much.
First of all, working with a dull knife is more dangerous than working with a sharp one. You need to put more pressure on a dull knife to make it cut, which could cause the knife to slip and cut you. A dull knife is still capable of giving you a nasty cut.
Secondly, not sharpening a knife when it needs sharpening will cause the edge of the knife to become chipped and damaged and will require a more aggressive sharpening to re-establish the edge. This will result in more material being removed from the knife.
TIP: It’s clear when you don’t sharpen your knives they become dull. But can be a knife too dull to sharpen? Find out the complete answer in the article below:
Can A Knife Be Too Dull To Sharpen? Here’s the Answer
Best Way To Sharpen Your Knife
There are many methods to sharpen a knife, and some remove more material from your knife than others.
Pull-through carbide or ceramic sharpeners remove a lot of material from the edge and leave the edge in a jagged state that will need further attention.
With these types of sharpeners, there is often no selection available to do a fine or a coarse sharpening; there is only one grit. Many knife owners find this type of sharpener too aggressive for their knives because they remove a lot of material from the edge.
Commercial sharpening systems are good because they can be adjusted to the coarseness required for the sharpening task. Thus, you can choose between an aggressive sharpening, a light sharpening, or even a honing.
Whetstones are also a great choice for the same reason. They come in multiple grits so that you can choose a stone of appropriate coarseness for the task at hand.
Whetstones or an appropriate sharpening system where the level of aggression of material removal would be the best method to choose from to remove the least amount of metal from your knife and still get the knife sharp.
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):
- Fixing stone: Whetstone SHAPTON Ceramic KUROMAKU #320
- Sharpening stone: Suehiro CERAX soaking whetstone: Medium #1000
- Finishing stone: Whetstone SHAPTON Ceramic KUROMAKU #5000
Our budget choice (Amazon link): Sharp Pebble Extra Large Sharpening Stone Set
While sharpening does remove metal from the knife, it is a necessary task to make sure the knife remains usable and effective for its intended purpose.
The amount of metal removed from the knife during sharpening can be limited by choosing a sharpening method that gives you flexibility in choosing the coarseness of the abrasive used on the knife.
Regular honing of the knife before or after use will extend the life of the edge of the knife and reduce the frequency of the sharpening sessions required on the knife.
TIP: When an inexperienced person sharpens a knife, they sometimes try to get the knife ultra-sharp. But can you oversharpen your knife? Find out everything you need to know about knives oversharpening in the article below: