Quantcast

Design improvement, convexing and grinding

Kitchen Knife Forums

Help Support Kitchen Knife Forums:

Delbert Ealy

Founding Member
Joined
Feb 28, 2011
Messages
1,152
Reaction score
0
Well I think I finally found the final key to kitchen knife perfection. The worst thing about it is that it was right under my nose the whole time. Let me explain.
When I first started on the kitchen knives I knew you guys were looking for lasers and so that is what I set out to make. I knew that most knifemakers starting out in kitchen knives make them too thick. I have always been a "thin knife" maker so I knew it wouldn't be a problem for me. However I was under the assumption that meant thin stock and full flat grinds, and that would be true in a perfect world, a full flat grind offers the least resistance and allow the angle of the bevel as shallow as possible for a given size stock. However, in the real world we have to deal with things like the experience of the person doing the cutting, the material being cut and the cutting board itself, and the type of knives the person doing the cutting is used to using. So, I make some knives and along the way I make some adjustments as a result of the feedback I am getting from those of you who have my knives, no real major things, mostly just a bit of tweeking. I am a very skilled knifemaker and in making one style of knife I expected such, it happens to all of us. I am contantly learning and I get better as I go along. Then I push things a bit far on the grinding and make them too thin, OK I learned my lesson there.
In the midst of that I get this from Salty
If you want to find the holy grail don't think flat. And thin is only as good as it functions.
This comment got me thinking however, because I do have the aspiration to make the absolute best knives I can. I started noticing comments here and there about convex bevels, and this really drove me crazy, because when I think of convex bevels I think of the grind on an axe or maybe a deba. Fast forward a month and I have a conversation with Johnnychance about this very issue and it all finally comes together. The convex grind that was mentioned is really not a true convex, but a partial flat grind that is blended. The blending is almost as important as the partial grinding, if its too much then it acts almost like a full flat grind, so too little is actually better than not enough blending, but there has to be a little blending. The key here (the one I missed) is about food release and resistance, not really about cutting ability, I know my knives can cut and well. With a full flat grind you have the best angle for cutting, but it also has a big surface area, and that contributes to food sticking. With a partial grind the angle is steeper, however the surface area is much less and the food just falls away from the blade. All new knives from now on will have the new grind, and will perform to a higher standard. With the extra steel left on this also affects the flex of the knife, which I know has been something that some of you have mentioned. This will also affect the balance, putting it a bit more forward.

I do want to thank all of you, my desire is to make the highest quality knives possible, I think this will be the final major step in the design.

Thanks,
Del
 

mainaman

Senior Member
Joined
Feb 28, 2011
Messages
1,271
Reaction score
0
Thanks for sharing Del, and yes IMHO flat grind is not best, I just can't imagine it has the optimal functionality.
I am big fan of Shigefusa grind, IMHO one of the best out there.
 

JohnnyChance

Founding Member
Joined
Feb 28, 2011
Messages
3,418
Reaction score
14
It was good talking to you last week Del and I am looking forward to seeing your new work!
 

Delbert Ealy

Founding Member
Joined
Feb 28, 2011
Messages
1,152
Reaction score
0
It was good talking to you last week Del and I am looking forward to seeing your new work!
Johnny,
It was a joy for me as well, my talk with you was the final step for me to make the jump to the idea that I could improve the performance of the knives I make. Thank you for pushing me to that conclusion. I meant to include you above and credit you for that, I do so now.
Thanks,
Del
 

JohnnyChance

Founding Member
Joined
Feb 28, 2011
Messages
3,418
Reaction score
14
Another issue with full flat grinds that is not food release or wedging but is sorta related to both, is if you are cutting something dense that is as tall as the blade (like a potato). The flat grind and product have a lot of surface area in contact with one another and it makes the knife feel like it is much thicker/duller than it actually is. It is just that there is so much surface tension and drag on the blade that you get resistance from the sides of the blade, not the edge.
 

Dave Martell

Forum Founder
Professional Craftsman
Joined
Feb 27, 2011
Messages
14,065
Reaction score
948
Location
Airville, PA
I'd also like to mention that your edges have really come a long way, great OTB go to work type stuff you're doing now Del.
 

Salty dog

Senior Member
Joined
Mar 4, 2011
Messages
2,294
Reaction score
6
Here on Lake Michigan we sometimes get waves called "rollers". Waves that never crest. Some of the best grinds remind me of rollers. The bottom gradually rising into a gentle peak, then falling into the beginning of another.

Del, my hat is off to you. I find some hardened knife makers aren't the most receptive to feedback. I feel your quest will be fruitful in many ways.
 

JMJones

Senior Member
Joined
Mar 3, 2011
Messages
417
Reaction score
0
Just a question from a fellow knife maker, are you doing the blending on a slack belt, rotary platen, on the stones or something else?

Thanks

John
 

Delbert Ealy

Founding Member
Joined
Feb 28, 2011
Messages
1,152
Reaction score
0
Here on Lake Michigan we sometimes get waves called "rollers". Waves that never crest. Some of the best grinds remind me of rollers. The bottom gradually rising into a gentle peak, then falling into the beginning of another.

Del, my hat is off to you. I find some hardened knife makers aren't the most receptive to feedback. I feel your quest will be fruitful in many ways.
Salty,
Thanks, In the larger knife world I have found many makers that are eager to learn, but there is always an old coot that thinks they know everything, well I'm not one of them. I know you guys have seen other makers jumping into making kitchen knives that just don't get it, and they move on. I don't want to be one of those, I still will make other knives, but all my focus is on kitchen knives. My ambition is to make a kitchen with the best qualities from your favorite knives, while keeping elements of my own style.
Thanks,
Del
 

Delbert Ealy

Founding Member
Joined
Feb 28, 2011
Messages
1,152
Reaction score
0
Just a question from a fellow knife maker, are you doing the blending on a slack belt, rotary platen, on the stones or something else?

Thanks

John
John,
As Salty pointed out above the grind should almost, but not quite crest, so I will probably do my blending with my final step, which is hand sanding, or maybe on a slack belt with the finest belt I use, then hand sand. If you blend too far it will be detrimental to the performance.
Thanks,
Del
 

El Pescador

Engorged Member
Founding Member
Joined
Mar 2, 2011
Messages
2,225
Reaction score
1
After reading this post, I contacted Del about putting together a knife for me. In the discussion I let him know that I'd be interested in a monosteel knife and Del had no problem with this. We discussed profiles and I ended up sending him a Carter and my ITK as references. He isn't going to copy the knives but plans on incorporating the cutting features in the new design. Also, it isn't going to be a laser, but it will still be thin. Del knows now that I want it a laser in the last third of the blade, but regular thickness in the heel and middle. After reading posts from people the consistency and quality of the grinds of him knives we never an issue, rather it was a fundamental design flaw that was an issue. My new knife will be a 240m gyuto. Del assures me that he will maintain his high standards on fit and finish. All this for $450! I'm so excited!
 
Last edited:

El Pescador

Engorged Member
Founding Member
Joined
Mar 2, 2011
Messages
2,225
Reaction score
1
After seeing his handles and talking to him about geometry and profiles I felt like he gets it. In sending him some of the best knives I have ever used, I am hoping he can use them to give him a "cheat" . I'm amazed that people who make knives don't look at other successful makers' products. We all have seen some bad examples that have shown up as posts on the board. It just seems logical. Both knives are users, not drawer queens. I wanted a knife like that, so I though "why not send him some really good examples?". Del was all for it. And at that price, why not!
 

UglyJoe

Senior Member
Joined
Mar 2, 2011
Messages
426
Reaction score
1
You might want to ask Del before posting a quoted price to you on a public forum...
 

UglyJoe

Senior Member
Joined
Mar 2, 2011
Messages
426
Reaction score
1
I will say that I love convexed geometry. It gives the knife presence as well as precision, and as others have said, I think it actually takes better advantage of the physics of cutting, particularly wet vegetable matter that we usually use a gyuto for. I want to eventually try a knife that is basically flat ground on one side and convex slightly on the other, just to see what it's like. An Aritsuga A type sharpened 99/1 with a hamaguriba would fit that bill...

Looking forward to the fruit of your labor, Del! I'm sure it will be amazing.
 

tk59

Founding Member
Joined
Feb 28, 2011
Messages
4,212
Reaction score
6
You might want to ask Del before posting a quoted price to you on a public forum...
+1

BTW, UJ, I have a couple of knives ground this way and another custom job on the way (hopefully). Personally, I like them quite a bit but they do take some getting used to (steering). They are basically like a very thin yanagiba. You do get some friction on the flat side, as well. I would assume that is why Glestain makes theirs with a slightly concave backside.
 

El Pescador

Engorged Member
Founding Member
Joined
Mar 2, 2011
Messages
2,225
Reaction score
1
I PMed Del about the price in the post. He's OK with it. I should have asked him b4 the post...sorry Del!
 

Michael Rader

Banned
Joined
Apr 14, 2011
Messages
285
Reaction score
0
Great thread. I've been getting lots of great feedback on my knives from a "pass-around" knife and also JohnnyChance lent me three knives out of his collection so that I can really analyze some features (good and bad) to help my work. The issue of a convex grind is becoming more and more important to me too, as some of the guys were having food sticking issues. As long as we keep learning and refining our work, we can stay in this business a long, long time with much success. Good luck, Del.
-M
 

Delbert Ealy

Founding Member
Joined
Feb 28, 2011
Messages
1,152
Reaction score
0
I got an interesting package in the mail today. I was sent a budget-line carter and a devin ITK. The owner of the carter said that if he could have just one knife it would be the carter. Although I have not yet cut anything with either knife I can already see where the style of grind on the carter would make a signicant difference in food adhesion. That is a change I will definately be making and I see it as a positive one. The ITK was as interesting in its own way, because it actually is convex ground, not very much; a degree, perhaps two. I will have to cut with it to see how much of a difference it makes, if any.
As Pesky mentioned above, starting with his knife and one other I will shortly be making a line of knives without using my damascus as the steel for the blades. The knives will have the same profile as my current knives, the only major change other than the steel will be that they will be partially ground for the reasons I stated in my original post. This has actually been brought up to me several times in the past few months, and originally I was against it. I wanted to just make the damascus knives. I have decided, however, to go ahead with a monosteel line in order to give more of you an opportunity to use my knives without shelling out the big bucks for the damascus. These will not be mid-tech knives, they will be full "customs" with all the attention to detail that I give to my damascus knives, and with the same high quality handles. My first choice for steel will be O-1, a steel that I have been using for years and that I know the heat treatment inside and out. For those of you that love 52100, I only ask that you open your mind that there are other high performance steels out there. I will also be making a few in AEB-L as well for those of you who prefer a little stain resistance. In trying to keep the price down on these knives, I have decided to offer a padded case for delivery on these knives rather than the wooden boxes I provide with my damascus knives. If you really want a box with your knife, that can be arranged for a slightly higher price.
Thanks,
Del
 

jm2hill

Founding Member
Joined
Jun 24, 2011
Messages
541
Reaction score
0
As Pesky mentioned above, starting with his knife and one other I will shortly be making a line of knives without using my damascus as the steel for the blades. The knives will have the same profile as my current knives, the only major change other than the steel will be that they will be partially ground for the reasons I stated in my original post. This has actually been brought up to me several times in the past few months, and originally I was against it. I wanted to just make the damascus knives. I have decided, however, to go ahead with a monosteel line in order to give more of you an opportunity to use my knives without shelling out the big bucks for the damascus. These will not be mid-tech knives, they will be full "customs" with all the attention to detail that I give to my damascus knives, and with the same high quality handles. My first choice for steel will be O-1, a steel that I have been using for years and that I know the heat treatment inside and out. For those of you that love 52100, I only ask that you open your mind that there are other high performance steels out there. I will also be making a few in AEB-L as well for those of you who prefer a little stain resistance.
Del,

this is fantastic news! A great option for some people (like myself) who couldn't spend 800-1000 dollars on a knife but would gladly spend 400-600 on a custom knife from a dedicated maker like yourself.

Looking forward to getting one of these. Maybe not in the near future, but definitely sometime.
 

Delbert Ealy

Founding Member
Joined
Feb 28, 2011
Messages
1,152
Reaction score
0
Great thread. I've been getting lots of great feedback on my knives from a "pass-around" knife and also JohnnyChance lent me three knives out of his collection so that I can really analyze some features (good and bad) to help my work. The issue of a convex grind is becoming more and more important to me too, as some of the guys were having food sticking issues. As long as we keep learning and refining our work, we can stay in this business a long, long time with much success. Good luck, Del.
-M
Thanks Mike,
I was wondering which of the other custom makers would respond to this particular message. From what I have seen of your work, I know you have a talent for making high quality knives. I am glad to hear you too are responding positively to this message. Take a close look at the knives Johnny is sending you, and I encourage you to use them as well. There are some things you will see in use that you will not get from just looking.
Thanks,
Del
 

tk59

Founding Member
Joined
Feb 28, 2011
Messages
4,212
Reaction score
6
...The issue of a convex grind is becoming more and more important to me too, as some of the guys were having food sticking issues...
The convex grind is about more than the sticking, per se. It is about minimizing drag or friction during the cut as well. I have some fairly thick knives (ie Heiji) that easily outcut thin, flat ground knives (for most jobs) due solely to this characteristic of the grind, as far as I can tell.
 

UglyJoe

Senior Member
Joined
Mar 2, 2011
Messages
426
Reaction score
1
My Mizuno is the same way. The thing about the Mizuno is that I have figured out how to sharpen it like a double sided single-bevel knife - not that there was much figuring out, it just went against my nature from using and sharpening my other double bevel knives. But this goes to what Del said about the convexing needing to be really just a slight blending of two planes. I sharpen at two bevels (one from the cladding down, the other from the cladding about halfway up the blade. This gives two very distinct bevels, until I blend them together with just a few "wavy" motions on the stones. It's not anywhere near a smooth curve, really two planes with the edge between rounded off. The performance increase I got out of the knife when doing this was astounding. The edge was thinner, a little bit, but really I think it was the way food naturally gets pulled away from the main body of the knife. It makes cutting very smooth. The added weight from the thickness of the blade above the bevels really allows the knife to do all of the work. It's because of this that I think we should start using a different term than wedging - for a very thick knife with poor geometry I think wedging describes what is going on well. But some thin knives "wedge", and really I think it's less wedging and more adhesion of the food to the side of the blade causing it to "stick".
 

El Pescador

Engorged Member
Founding Member
Joined
Mar 2, 2011
Messages
2,225
Reaction score
1
The odd thing is the ITK is a convex grind and the Carter is a partial grind. Both work!
 

El Pescador

Engorged Member
Founding Member
Joined
Mar 2, 2011
Messages
2,225
Reaction score
1
So here's an update...Del got the steel in today for my knife! He's got some forging to do but he's planning on getting to work on the knife early next week. Another thing we decided on was doing a leather saya-like sheath. Del doesn't do anything half-assed. The sheath is going to be glued and stitched, and have a thick welt to protect the stitching from the sharp edge. This is going to be an additional cost, but I believe it will be well worth it!
 

jm2hill

Founding Member
Joined
Jun 24, 2011
Messages
541
Reaction score
0
So here's an update...Del got the steel in today for my knife! He's got some forging to do but he's planning on getting to work on the knife early next week. Another thing we decided on was doing a leather saya-like sheath. Del doesn't do anything half-assed. The sheath is going to be glued and stitched, and have a thick welt to protect the stitching from the sharp edge. This is going to be an additional cost, but I believe it will be well worth it!
Pesky keep us updated!

This is something I'm very excited and intrigued about!
 

tk59

Founding Member
Joined
Feb 28, 2011
Messages
4,212
Reaction score
6
So here's an update...Del got the steel in today for my knife! He's got some forging to do but he's planning on getting to work on the knife early next week. Another thing we decided on was doing a leather saya-like sheath. Del doesn't do anything half-assed. The sheath is going to be glued and stitched, and have a thick welt to protect the stitching from the sharp edge. This is going to be an additional cost, but I believe it will be well worth it!
I'm sure you can barely stand the excitement, lol! You need to leave that poor man alone to get some work done!
 
Top