The 8 inch ZK Damascus is definitely a looker, but far from a performer. While I very much appreciate its appearance, it has been sitting in the drawer for a long long time. The knife has a great balance as a western, a thin spin, a good distal taper, and a decent core steel (SG2). However, the performance is poor: everything you cut sticks to the blade and the friction/drag is unbearable when cutting firm-textured produces. It's a pure looker.
Before the holidays, I had the ZKramer in my hand again. Feeling the elegant balance, I started to think: let me try another western handle knife, but this time a real performer. The search was difficult, I was looking for something rivals Konosuke's grinds, balanced at the bolster, western handled, 210mm in length, and stainless. When I finally was ready to buy, some drama happened on the seller's side and I didn't get it. Anyway, even if I bought the knife, it still wouldn't get close to a Konosuke grind.
So what grind makes a kitchen knife perform (like a laser)? From my perspective, the blade has to be thin, especially behind the edge. When that part is thinned enough, the knife will just drop through smaller vegetables, such as celery and small carrots. However the blade can't be too thin for two reasons: 1. it must have enough strength behind the edge; 2. it has to be thick enough to afford a slight convex grind for food release. Why a slight convex? A pronounced convex means your blade is thick, and that will cause wedging on larger vegetables.
Zwilling did a bad grind job on the ZK Damascus. The already thin blade has a flat grind starting from the spine. But that grind doesn't go all the way to the edge, it stops at about 7~8mm before that, then ground at a higher angle towards the edge. No wonder the knife wedges, drags, and sticks. Good news is the SG2 core is pretty hard so that it can afford further thinning.
All that said, I'm actually very new to thinning/regrinding. What's worse, the best tools I have for this job are some diamond stones. So this is a multi-day project.
The knife started at 277 grams. It sounds heavy, but actually feels nimble at hand.
The nickel-stainless Damascus layer turned out to be very abrasion resistant. Initially I tried a Shapton Pro 220, but it barely cut. Even a 140 diamond stone cut slowly. Finally the 80 grit diamond came to the rescue, but I was greedy by thinning too much with it and that left deep scratches:
I wanted to keep some original pattern and the "Kramer Zwilling" label, so I covered them with duct tapes. But to my surprise, the label (ink) was entirely lifted by the duct tape:
So I went further (angrily) grinding all the Damascus away. The tip was ground as thin as I dare:
The left side (in normal holding pose) of the blade becomes almost flat, and the right side has a slight convex. I had a better convex on the right side, but I mistakenly ground it away when trying to remove deep scratches (be patient and don't do that in the first place!). Lengthwise I did a differential grind which left the blade thicker towards the heel to keep some "workhorse" feel to it. The choil shot:
The blade was taken to a 600 grit finish (lower grit scratches are still visible, but I have no more elbow grease left), and buffed using a Dremel. Before re-etching, I put a 8k low angle edge with micro bevels, covered with duct tape, then used my wife's least favorite nail lacquer to cover the core steel below the lamination line. Using Murray Carter's method (although I don't agree with his partnership with nanohone, his method worked), I brushed both sides with full strength RadioShack PCB enchant and left it there for 1 minute.
Look at the etching result. Isn't this a dark magic?! The re-etched Damascus finish covered up all the scratches I was worrying about, and in cutting tests it didn't add any negative effects. It is unclear if the performance would be the same if the core steel below the lamination line was also etched.
Finally, some beauty shots!
Performance-wise, the knife had a total reborn. The front portion is so thin which just flies through anything. The tip simply drops through celery, carrots, and onions, no force needed. The back portion is a little bit thicker. With a tad more convexity, it has a little bit better food release than the front - see below for the chopped potato, nothing stuck to the blade:
The hand grinding was an ordeal, but I'm very pleased with the result. The knife now has the Zwilling label ground away, but a part of me etched in. Special thanks to my friend (he looks like Kurosaki san's twin brother), whose Konosuke YS inspired me about the grind. And thanks to my wife who always bear with me on my hobbies. Finally, thanks to all the knife people who share their knowledge and discoveries without reservation!
Before the holidays, I had the ZKramer in my hand again. Feeling the elegant balance, I started to think: let me try another western handle knife, but this time a real performer. The search was difficult, I was looking for something rivals Konosuke's grinds, balanced at the bolster, western handled, 210mm in length, and stainless. When I finally was ready to buy, some drama happened on the seller's side and I didn't get it. Anyway, even if I bought the knife, it still wouldn't get close to a Konosuke grind.
So what grind makes a kitchen knife perform (like a laser)? From my perspective, the blade has to be thin, especially behind the edge. When that part is thinned enough, the knife will just drop through smaller vegetables, such as celery and small carrots. However the blade can't be too thin for two reasons: 1. it must have enough strength behind the edge; 2. it has to be thick enough to afford a slight convex grind for food release. Why a slight convex? A pronounced convex means your blade is thick, and that will cause wedging on larger vegetables.
Zwilling did a bad grind job on the ZK Damascus. The already thin blade has a flat grind starting from the spine. But that grind doesn't go all the way to the edge, it stops at about 7~8mm before that, then ground at a higher angle towards the edge. No wonder the knife wedges, drags, and sticks. Good news is the SG2 core is pretty hard so that it can afford further thinning.
All that said, I'm actually very new to thinning/regrinding. What's worse, the best tools I have for this job are some diamond stones. So this is a multi-day project.
The knife started at 277 grams. It sounds heavy, but actually feels nimble at hand.
The nickel-stainless Damascus layer turned out to be very abrasion resistant. Initially I tried a Shapton Pro 220, but it barely cut. Even a 140 diamond stone cut slowly. Finally the 80 grit diamond came to the rescue, but I was greedy by thinning too much with it and that left deep scratches:
I wanted to keep some original pattern and the "Kramer Zwilling" label, so I covered them with duct tapes. But to my surprise, the label (ink) was entirely lifted by the duct tape:
So I went further (angrily) grinding all the Damascus away. The tip was ground as thin as I dare:
The left side (in normal holding pose) of the blade becomes almost flat, and the right side has a slight convex. I had a better convex on the right side, but I mistakenly ground it away when trying to remove deep scratches (be patient and don't do that in the first place!). Lengthwise I did a differential grind which left the blade thicker towards the heel to keep some "workhorse" feel to it. The choil shot:
The blade was taken to a 600 grit finish (lower grit scratches are still visible, but I have no more elbow grease left), and buffed using a Dremel. Before re-etching, I put a 8k low angle edge with micro bevels, covered with duct tape, then used my wife's least favorite nail lacquer to cover the core steel below the lamination line. Using Murray Carter's method (although I don't agree with his partnership with nanohone, his method worked), I brushed both sides with full strength RadioShack PCB enchant and left it there for 1 minute.
Look at the etching result. Isn't this a dark magic?! The re-etched Damascus finish covered up all the scratches I was worrying about, and in cutting tests it didn't add any negative effects. It is unclear if the performance would be the same if the core steel below the lamination line was also etched.
Finally, some beauty shots!
Performance-wise, the knife had a total reborn. The front portion is so thin which just flies through anything. The tip simply drops through celery, carrots, and onions, no force needed. The back portion is a little bit thicker. With a tad more convexity, it has a little bit better food release than the front - see below for the chopped potato, nothing stuck to the blade:
The hand grinding was an ordeal, but I'm very pleased with the result. The knife now has the Zwilling label ground away, but a part of me etched in. Special thanks to my friend (he looks like Kurosaki san's twin brother), whose Konosuke YS inspired me about the grind. And thanks to my wife who always bear with me on my hobbies. Finally, thanks to all the knife people who share their knowledge and discoveries without reservation!
