Over-sharpening a knife can actually damage the edge and make it duller. It's important to sharpen a knife only when it needs it, and to sharpen it to the correct angle.
As u/knifeq2121 said, you can't ruin a knife by sharpening it, unless your using a very coarse stone and pressing with all your strength.
Using the Wrong Pressure or Angle
It's important to maintain a constant angle when sharpening and to also make sure you're applying the right amount of pressure. Too much, and you could end up with damage to your knife. Not enough, and it's not going to get sharp like you want it to.
Even the adjustable ones are not well suited to all knives. Electric pull through sharpeners remove way too much metal and shorten the life of your knife by years. Ceramic wheel sharpeners tend to take chips and chunks out of thin Japanese blades.
The more you sharpen a knife, the sharper it will get
This is not true. Over-sharpening a knife can actually damage the edge and make it duller. It's important to sharpen a knife only when it needs it, and to sharpen it to the correct angle.
It's just some, like ceremic knives, are hard and brittle and need special equipment to sharpen them, like diamond Lapping. Ceremic blades are harder than normal honing stones, so, will not make any sharpening effort. However, pretend rubber knives are only for show and definitely cannot be sharpened.
Sharpening is the practice of aggressively polishing a knife to reform its edge. You'll only need to do this for very dull knives. In the process, bits of metal are actually shaved away. That's why sharpening a metal blade calls for material harder than steel, such as stone or ceramic.
Don't run your knife through a knife system or device. Running your blade through a device will unevenly chew up the edge, can scratch the face of the blade, and will not get your knife as sharp as using a whetstone to sharpen. Do not belt sharpen knives.
Firstly, let's clarify that there is no such thing as a knife that never needs sharpening. Every knife loses its sharpness over time and with frequent use. However, there are knives designed to last longer without losing their sharpness compared to traditional knives.
Most pros would agree that pulling the blade edge across the whetstone produces the best results. Not only will it bring the knife to its sharpest but it's also a much more effective way to remove chips and imperfections from the blade.
The stone may degrade in quality. There are some whetstones that are made from materials that won't hold up well when continually submerged in water. The materials will start to disintegrate and your stone will be rendered useless. This is more typical of synthetic stones than it is natural ones.
A whetstone can help you to keep the blade of a knife nice and sharp with just one or two strokes, which saves time in the kitchen.
The short answer is yes, a knife can be too sharp.
How to use a Manual Knife Sharpener: Place the knife against the coarse side of the sharpener and swipe it across the surface around ten times. This initial step sets the foundation for a sharp edge. Afterwards, switch to the fine side of the sharpener and repeat the swiping motion ten times.
In the world of knife sharpening, there's a fine line between perfection and overkill. Over-honing a knife can lead to a blade that doesn't just lack the desired sharpness but is also structurally compromised. To avoid this situation, approach sharpening with a thoughtful and restrained hand.
The last step in sharpening is removing the burr – the hide side of an old leather belt will do, or buy a strop such as this one. A bit of baby oil on the leather will help you get a nice, even covering of the polishing compound. As with most things, you get what you pay for.
While some stones – like those made of diamond or ceramic – can be used dry, they still usually benefit from a little water. Soaking the whetstone is important because it helps protect the stone from damage and wear. Sharpening your knives with a dry stone won't hurt the knife, but it will damage the stone over time.
While most cheap serrated knives can be sharpened and made to be as sharp as more expensive serrated knives, micro serrated knives cannot be sharpened. These are recognised by the sharp jagged cutting edge.
Never cut on glass, ceramic or countertops. Those surfaces are harder than a knife's edge and will quickly dull the blade. It's what you cut on that dulls knives, not what you're cutting.
Sharpening Angle Too High
Essentially, if you are working at too high of an angle, you may be blunting your edge. In practice, an angle that is only slightly too steep will not dull the edge. Only very high angles will create edges that feel dull.
The answer is fairly simple. Yes, old knives can be sharpened as long as they are in okay shape.
We do not recommend using sharpening or honing steels on Japanese knives. That's because Japanese knives are made from very hard steel — alongside the tapered V shape, this harder steel contributes to the effortless feel of Japanese knives.