Category: Sharpness
New Study on CATRA Testing of 8Cr13MoV
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Thanks to the guys at Knife Talk podcast for featuring me in the “Community Showcase.” Listen here.
Does Sharpening with a Grinder Ruin Your Edge?
Update: Michael Drinkwine sent me another report from Global where they reported factory sharpened and waterstone sharpened knives. I added it to the “CATRA Testing” section of the article.
Does Acidic Food Affect Edge Retention?
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I was interviewed on the Knife Junkie Podcast, so make sure you check that out.
Acidic Food
Carbon steel knives are frequently used in kitchens, probably the majority of them made by Japanese bladesmiths and knife companies. Kitchen knives cut a variety of foods, and some of them are corrosive. There has been some debate about whether any of these potentially-corrosive foods can actually affect sharpness or edge retention of kitchen knives. Sharpness is controlled by the radius/width of the edge. You can read more in the article on sharpness vs cutting ability.
The Sharpest Youtube Channel in the World
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Kiwami Japan
A popular Youtube channel called “kiwami japan” includes several videos of making knives out of unusual materials such as jello, pasta, chocolate, etc. The video on making a knife out of cardboard has over 20 million views which means that these videos have reached a broader audience than just knife makers or enthusiasts. As a materials engineer I find the videos interesting from a materials perspective, but they are entertaining in other ways as well. The videos are a bit quirky so I decided to take a dive into these videos and try to figure out what is going on. I also e-mailed the person who makes the videos and he answered a few of my questions. I will refer to him as “Kiwami” for the rest of this article though I know that is not his name. Kiwami means extreme in Japanese.
Sharpness vs Cutting Ability
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CATRA, Sharpness, and Cutting Ability
I got several good comments on the article about CATRA edge retention testing regarding sharpness and cutting ability. The edges tested with more acute angles (20° edge is more acute than 50°) started out cutting better and remained that way through the standard 60 cuts. However, the measured width of the edge with the worn 20° edges was larger than with the 50°. So this leads to a question: which was sharper? And if the 50° was indeed sharper due to its narrower edge then why was it not cutting as well?