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knife edge grinds

Sun Aug 25, 2013 12:11 pm

I'm trying to understand why the edge/bevel on my last two knife purchases don't have that distinct 1/16"ish bevel that is produced from mine and others sharpening stones. I've been doing a little research and my current guess is that they are coming with a convex grind possibly which is why it looks like the knife edge is seamlessly blended into the overall blade. For example the Richmond AEB-L laser looked this way to me and I simply chalked it up as a potential characteristic of a very thin knife. Then I noticed my new Konosuke Fujiwara also came with a similar edge. Now when I looked at the edge under a loupe I could see a very small bevel, but it was still a far cry from the knife edge pictures posted and produced.
Can someone explain to me what I'm seeing please? In order to get that 1/16" bevel that I'm used to from my edge pro is it going to be akin to reprofiling the edge?

Thanks

Re: knife edge grinds

Sun Aug 25, 2013 1:52 pm

Well, there are a couple of things that can cause what you are seeing.

1: The knife was ground extremely thin behind the edge and almost no matter how steep you sharpen it (within reason) there just isn't enough steel to make a wide-looking bevel.

2: The edge is sharpened closer to 20 degrees.

It's not that the edge is convexed. You will still see a convex bevel the same as you will see a flat bevel, but if you aren't seeing very much edge then chances are the knife is already very thin or needs to be sharpened a little bit steeper. I hope this helps. :)

Re: knife edge grinds

Sun Aug 25, 2013 4:26 pm

Yes it does help Shaun thanks. I'm guessing considering the two knives in question that my situation is the former rather than the latter. I tried checking the box edge with a marker and 15 deg. It came right off, but there is so little bevel to work with that the stone might have swiped it off at varying degrees. That's just a guess though.

Re: knife edge grinds

Sun Aug 25, 2013 4:59 pm

Many Japanese knives are ground very thin behind the edge and the bevel is almost a micro bevel and can be hard to see. This isn't a bad thing or an issue, it is just different than how other knives are ground. You do not need a 1/16" wide bevel to perform well. A wider bevel means that the knife is thicker behind the edge or needs thinning, or someone did a wide bevel and polished it like that for some reason? When people thin out a knife, it often gets the wider bevel look. I use a belt sander to regrind/thin my knives when needed, so that usually keeps my bevels nice and small.

Re: knife edge grinds

Sun Aug 25, 2013 5:14 pm

I also noticed this. What angle are the AS Laser gyutos sharpened to? How are they finished?

Re: knife edge grinds

Sun Aug 25, 2013 6:02 pm

You cannot use a factory grind as a template.

Unless you can tell its been done by hand on stones all factory machine ground edges are only there to get a "sharp" knife out the door.

Re: knife edge grinds

Mon Aug 26, 2013 11:21 am

When I received my Konosuke Fujiwara Blue #2 Funayuki/Gyuto 240mm I observed an edge that was different from others I had seen. The primary bevel started at the shionogi line and went all the way to the edge. So I pulled out my loupe and saw that there was a hairline micro-bevel on the edge. This micro-bevel was only on the right side, not the left. I haven't even sharpened it yet because it is very sharp already and I have to figure out how to sharpen it without messing the bevels up.

Re: knife edge grinds

Mon Aug 26, 2013 11:41 am

Badboy - You are able to more eloquently describe what I was seeing as well. I'll be interested in hearing what you do long term and what others with this knife do to keep it sharp. I ran a progression of high grit chosera stones across mine in an effort to simply refine it. Thanks for the update.
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