Tormek Community Forum

In the Shop => Knife Sharpening => Topic started by: John_B on September 01, 2019, 05:37:55 PM

Title: Toothy Bevel Discussion
Post by: John_B on September 01, 2019, 05:37:55 PM
On a Facebook knife sharpening page there is a discussion on making the bvel less polished or toothy as they describe it. Here is a post. Does this make any sense to you? If so what am I missing?

"think of the edge bevel like a saw. The scratch pattern creates tiny serrations or teeth. The more refined or polished the smaller the teeth. Like the difference between a saw blade for metal and for wood. The larger the teeth the better the blade will grab when using a slicing motion. The more polished a bevel is the less pressure needed for push cuts. So how "toothy" or polished you want a bevel depends on the use of the blade"
Title: Re: Toothy Bevel Discussion
Post by: wootz on September 02, 2019, 01:05:53 AM
The "micro-serrations" concept contributes to the confusion as people tend to mistakenly generalize properties of the serrated edge onto the microscopic level of a ragged coarse edge. The saw teeth and the edge apex ragged by coarse scratches are not the same.
I've been there, it is a dead-end.

In his article about chipping of the edge https://knifesteelnerds.com/2018/05/28/chipping-of-edges/ (https://knifesteelnerds.com/2018/05/28/chipping-of-edges/)
Larrin explains why coarse edges are more prone to chipping, an excerpt: "... a knife edge sharpened to rougher finishes will have larger scratches than a finely sharpened edge, and these scratches can be thought of as pre-existing flaws."

Even those who favour the coarse "toothy" edge admit that the knife dulls faster as the "teeth" get broken off.

Meat plants are well aware that knives with coarse edges worsen product presentation and increase operators' fatigue and repetitive strain injuries. On the contrary, polished edges improve product quality through higher value cuts and increase throughput.

Premium wear-resistant knife steels are plainly incompatible with unpolished edge.
.
Title: Re: Toothy Bevel Discussion
Post by: John_B on September 02, 2019, 04:17:16 PM
Thank you for the article it is an interesting read.

The myths that are so prevalent in the knife sharpening world abound. It is difficult even in the face of scientific proof to convince many of the believers.
Title: Re: Toothy Bevel Discussion
Post by: John_B on September 04, 2019, 03:12:48 PM
Ken, as you know I agree with you assessment of Facebook and the page in question. However, I am puzzled how it relates to a toothy edge discussion.
Title: Re: Toothy Bevel Discussion
Post by: Ken S on September 04, 2019, 04:40:52 PM
John,
You are correct. My post really does not apply to a toothy edge discussion. I should probably not have posted it. While I am very reluctant to take down a member's post, I am less reluctant to remove one of my own. My reply serves no useful purpose; I am removing it.

Ken
Title: Re: Toothy Bevel Discussion
Post by: John_B on September 05, 2019, 03:07:41 PM
No need to remove it. I was just wondering if I was missing something. Sort of like the American Literature class I had to take in college; great stories but I never could see the messages the professor said was there.
Title: Re: Toothy Bevel Discussion
Post by: Ken S on September 05, 2019, 04:06:54 PM
John,
No big deal about me removing my post. I am harder on myself than on other members. I don't think anyone is missing any major message without that post.
Ken
Title: Re: Toothy Bevel Discussion
Post by: Sharpco on September 08, 2019, 11:47:24 AM
I don't know exactly. But I know that many Koreans said "For kitchen knives except sushi knives, it is best to finish with 2K~5K." They use whetstones like Chosera, Shapton Pro etc.