Interesting article that explains single bevel blades and includes good diagrams with Japanese terminology for the different parts of the blade, and other useful information.
https://knifewear.com/blogs/news/single-bevel-sharpening
The first step in sharpening is being able to identify the type of blade grind and understanding how that particular grind "works" and how its features affect how it must be sharpened.
Sharpening a single bevel knife as you would a traditional western style double bevel grind will result in reduced cutting performance and can cause problems that are very difficult for even an experienced sharpener to repair. In the worst case, it could actually ruin the knife.
Here's a video of a knife with similar issues as the one repaired in the article. It's all in Japanese, but if you read the article first, you'll be able to tell what's happening and why. The video provides a good idea of how long it can take to correct an improperly sharpened single bevel blade. It's worth noting that this repair was not as extensive as the one in the article as the urasuki was left alone.
Can you see at least two flaws in the final sharpened blade? I see two. I suspect that one was left intentionally because it would have been too complicated and difficult to repair. The other may have just been an oversight, or it could have also been the result of having reached the limit of time and effort the sharpener was willing to spend on that particular repair.
Can you explain why he waited to clean the blade until after it was sharpened?
Notice that any time the back of the blade is touched to the stone, it is perfectly flat against the stone. This is done to remove burrs or to restore the uraoshi--never to put any kind of a bevel on that side.
By the way, although scissor blades are, in many ways, quite unlike the knives discussed in the article and shown in the video, they are alike in one way--they are single bevel ground. That means that only ONE surface on each scissor blade is ever sharpened.
Here's a resource with a number of Japanese terms relating to knives and blades. Not all of the definitions are really good, but you can use the terms in searches to find more information.
http://zknives.com/knives/kitchen/misc/jpnktknvterms.shtml
https://knifewear.com/blogs/news/single-bevel-sharpening
The first step in sharpening is being able to identify the type of blade grind and understanding how that particular grind "works" and how its features affect how it must be sharpened.
Sharpening a single bevel knife as you would a traditional western style double bevel grind will result in reduced cutting performance and can cause problems that are very difficult for even an experienced sharpener to repair. In the worst case, it could actually ruin the knife.
Here's a video of a knife with similar issues as the one repaired in the article. It's all in Japanese, but if you read the article first, you'll be able to tell what's happening and why. The video provides a good idea of how long it can take to correct an improperly sharpened single bevel blade. It's worth noting that this repair was not as extensive as the one in the article as the urasuki was left alone.
Can you see at least two flaws in the final sharpened blade? I see two. I suspect that one was left intentionally because it would have been too complicated and difficult to repair. The other may have just been an oversight, or it could have also been the result of having reached the limit of time and effort the sharpener was willing to spend on that particular repair.
Can you explain why he waited to clean the blade until after it was sharpened?
Notice that any time the back of the blade is touched to the stone, it is perfectly flat against the stone. This is done to remove burrs or to restore the uraoshi--never to put any kind of a bevel on that side.
By the way, although scissor blades are, in many ways, quite unlike the knives discussed in the article and shown in the video, they are alike in one way--they are single bevel ground. That means that only ONE surface on each scissor blade is ever sharpened.
Here's a resource with a number of Japanese terms relating to knives and blades. Not all of the definitions are really good, but you can use the terms in searches to find more information.
http://zknives.com/knives/kitchen/misc/jpnktknvterms.shtml
