How thin is too thin with gyuto bevel/edge?

JG Custom Metal Works

JG Custom Metal Works

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Nov 27, 2013
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So, I'm just finishing up a gyuto for a customer and the bevel is extremely acute. It pretty much goes to a zero edge. I was planning on putting a secondary bevel on the edge at a more obtuse angle, but I'm not sure if it would still be too thin. The blade is made from 1084 and thickness is 1/8 on the flats. I haven't sharpened the knife yet. I took some measurements of edge and bevel thickness.

At the very edge(not sharpened yet) - .005
1/4" from the edge- .024
1/2" from edge- .053
3/4" from edge- .068

Does that sound too thin? I haven't made a ton of kitchen knives and want to make sure this will work well for the customer. It will likely be used for chopping veggies and other soft material.


Here's the knife in question:

Boy they really screwed up the process for posting pics. Bear with me. Trying to get them up. Well shit this is frustrating. Not sure if I'll be able to post pics
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That thin id want to be around 60+. I use 52100 and aebl. I take my 52100 to 63 and aebl to 62. I use metric for my knives because its easier and saves time. That said 5mm back (about .25") my knives are .6mm or less so about the same range as you, bit my grinds only go 1/3rd up the blade.. above that i keep it meaty for food release and since i use 3/32 stock its still thin enough to not wedge. If the grind goes up much higher food stiction becomes annoying without thinning BTE even more manually. If i want my grind higher i do a separate grind and blend to get controlled convex. I think youll be fine by setting a more obtuse angle. Just go cut some butternut squash and see how it handles, at 58 chipping isnt an issue, just test to see if edge rolls durinf use. I think your knife will be fine
-Trey
 
I was thinking I could always grind the edge back a little bit. Maybe to .010 at the edge...

The guy I'm selling to isn't a master chef or anything
 
.005" at edge before sharpening will be fine. Cutting edge will blow his mind. Seriously though if in doubt just sharpen and go whack it on a cutting board some. If worried then just grind it back. I really wouldnt go thicker than .005" before sharpening on a kitchen knife though. Then again I havent tested that steel at that hardness. Maybe grind back to .007" and sharpen if youre that worried?
-Trey
 
You could try to flex it a little with your fingernail and see if it chips at all. I'd put a secondary bevel on it.
 
sounds perfect to me, except the 58 is too low IMO, I like 64 RC myself. but I like a thin hard edge :)

how high is your heel, 2"?
have a look at Murray Carter's knives online, often around 2" at the heel and less than .1 at the spine. That equals a very thin edge

I made a couple kitchen knives at his shop under his guidance, Murray hammers them out very thin. Thin cuts, thin works. But I tell my customers, no bones.

no such thing as too thin in a kitchen knife :)
 
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JG Custom Metal Works said:
So, I'm just finishing up a gyuto for a customer and the bevel is extremely acute. It pretty much goes to a zero edge. I was planning on putting a secondary bevel on the edge at a more obtuse angle, but I'm not sure if it would still be too thin. The blade is made from 1084 and thickness is 1/8 on the flats. I haven't sharpened the knife yet. I took some measurements of edge and bevel thickness.
At the very edge(not sharpened yet) - .005
1/4" from the edge- .024
1/2" from edge- .053
3/4" from edge- .068
Does that sound too thin? I haven't made a ton of kitchen knives and want to make sure this will work well for the customer. It will likely be used for chopping veggies and other soft material.
Click to expand...

for a slicing kitchen knife, I would be 0.02 1/4" up, 0.03 1/2" up. I also like higher hardness, at least Rc62. Rc58 will work, the edge will bend a touch rather than chipping. go ahead and sharpen. see how it works on meat and veg. the blade should work very well doing pull cuts/slicing.
 
Once you grind it that thin you have it where you want it. Now is the time to "optimize" your secondary bevel angle. If you have the inclusive angle too small the steel will tend to chip/flake off when stropping and cutting. When you raise a burr during sharpening it will be maybe too big and cause areas of the edge to break premature. What you want to do is slowly increase that inclusive angle until you get the kind of edge stability and performance you are after. Your exact numbers/ measurements at this point dont matter too much as they will vary with the steel type, geometry and heat treat of each blade you make. I like to perform this test on carrots but you could use any number of different things. The key really is to optimize the edge for each knife you do by testing. Experienced cooks will notice this stuff right away.
 
i had the same question about a month ago. I had a santoku that was really flexible 2" short of the tip. I was finish grinding it and burned a hole right through about 1/2" above the edge. I have since changed my grinding style...
 
I do mine a bit harder, but about that thick. I like the edge thickness on a kitchen knife to be in the 4-8 thou range.
As long as you can cut up a cabbage without worry of damage, I feel it's thick enough for a general purpose kitchen knife
 
Geoff Flato said:
I do mine a bit harder, but about that thick. I like the edge thickness on a kitchen knife to be in the 4-8 thou range.
As long as you can cut up a cabbage without worry of damage, I feel it's thick enough for a general purpose kitchen knife
Click to expand...
only if it's a boneless cabbage of course.
 
Few people today have ever seen a bone in cabbage.

Since the 70's, when the invented the automated cabbage deboning harvester, all commercial cabbage is boneless. If you deal with a direct farm source, you have to cut the stalk off at the base of the head and pull out the bones with pliers. Its pretty simple, but still takes time. I haven't done it in years.
 
0.005" is mid range for a well heat treated kitchen knife. Your knife is too soft, and you will probably get some edge rolling. Some consider anything over 0.007" a club. I tend to go about 0.003" or so, and Rc62+.
 
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