caso0O0omie (kasumi: a first attempt)

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nakiriknaifuwaifu

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Hello:

I recently purchased a JNat to try and figured it was time to learn how to polish.

I have a couple years of sharpening experience now, albeit low-volume. However, I haven't really owned any non-stainless or wide bevel knives - or any formally Japanese knives for that matter (discounting my tojiro; it was miserably warped and I elected to return it). My daiso nakiri had been my trusted partner for almost 3 years, until I had to leave it behind when I moved a few months ago.

I have been fortunate to have some cooking enthusiast and chef friends who lend me their jp knives to sharpen and use, but now it's time to learn some skills and buy a knife for myself. Kasumi is one of the things I would like to get down before I sink some cash and take the plunge, and that's what this thread is about.

A big thanks to @BillHanna for selling me his knife and to @Forty Ounce for the advice.

Materials:
Cerax 1k
Cerax 3k
Shiro Suita Koppa (unknown mine, maybe 5k - 8k grit?)

I'll add pictures as I go along!
 
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So here's the knife: a 165mm Moritaka Nakiri in iron-clad AS.

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Ok, first came the Cerax 1k. I chose to start on this because the wear on the bevels didn't seem too bad. I figured a few minutes on the stone would tell me if I needed to bring out the sandpaper.

Close of up the old bevel:

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First pass on the Cerax 1k:

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I was able to get the bevels relatively flat, but there was a small patch near the tip of the knife that was slightly concave. I was making small, light strokes like the video here:

I found a few scratches to be quite deep, so I thought I would continue for another couple of passes.

Post-Cerax 1k:

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The right side bevel had more scratches on the left. Not sure why. Onward to the 3k.
 
The Cerax 3k is my absolute favorite stone to use. Technique wise, not much more to share here. The same deep scratches remained, to my dismay.

In any case, here's where it got me:

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I'm missing the middle of the bladeroad at the tip. Maybe I'll iron that out one day.

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Now the koppa. This was my first time using a JNat, and I spent some good time on it. Tried not to contaminate it with other grits from my synthetic stones, so swapped out all the water, wiping material, and washed my hands.

I really like the renge pattern.

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The shinogi line is very uneven, but it doesn't look splotchy in person (I think). The following pictures are more flattering, but I'm including these because it shows the two kireha side by side.

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I was pleasantly surprised with the steel. It sharpens quick, and gets very sharp too. Push cuts on a paper towel.

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1/3 - Before

Time flies and it's mid-November. Finally, I've been able to get around to refinishing the edge. Let's make this journey a trilogy.

Here are how things are with patina. If you squint hard enough, it looks like a Jiro.

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So last we left things, the bladeroad was not fully finished. As you can see, there are some spots that still have vertical grind marks. These areas are concave.

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Let's get to it!

To be continued...

Will add pictures as I continue.
 
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2/3 - Coarse work

First stop, 400 grit wet/dry sandpaper.

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Tried a little hamaguri action, turned out okay??? Not really sure. Food release was godly before, haven't spent time with the knife post sharpening to say if there's been a change. A good portion of the hamaguri might have been my wobbly hands...

Low spot on one of the sides, shinogi line turned wonky.

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So I flattened my stones with a cheap diamond stone ($20 on amazon) and it turns out some large diamonds embedded themselves onto my stone. I broke the stone in with a metal wrench and re-flattened the stone with my usual sandpaper to make sure everything was smooth, BUT WHAT DO YOU KNOW - THERE'S A GIANT GASH ON ONE OF THE SIDES.

Tried breaking out the #220 AlOx sandpaper but that wasn't enough. The results are below. It'll take a bit more steel before that comes out. Lesson learned.

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Here's how things looked after I hopped back on the 400.

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3/3 - Fine work and Polishing

Alright so here we go...

Cerax 1k:
Tried to get things as clean as possible without any streaking. Used thicker mud and lighter pressure than I usually would, and got a consistent result. I would often get stiction to the stone when the mud got a touch too thick, so it was a fine balancing act with water. Spent too long on the stone and the metal started rusting. Oh my reactive darling moritaka steel...:upsidedownspin:

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Cerax 3k. More of the same. I have a hunch the left side polishes a lot easier than the right side. I have no idea why that is, but I don't get nearly as much streaking as on the right kireha. This time, I got a far more muted contrast with the 3k. I've never seen this before, and I wonder why it turned out this way. Maybe using more pressure would create better contrast.

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3k Bladeroads comparison (with mud):
I took some mud on a paper towel and rubbed it lengthwise to blend things in before I hit it with a koppa. I liked that it helped hide the scratch pattern. Will probably keep doing that.

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On to the koppa:

Used firmer pressure here, got some contrast back on the knife. Things got dark so these are the only pictures (under warm lighting) I have for now.

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Let's see if I can take more pictures in daylight. Would love to hear comments and advice.

Cheers and thanks for reading,
NKW
:dancingcow:
 
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Good looking! If your left side is being problematic, look if the blade needs a slight straightening. Since the profile is so flat it gets very sensitive to that.
 
What a beautiful morning, @RDalman sensei has noticed me >///////< uwu

How do I tell if something is crooked - is it just the spine, or is there a way of sensing warps and wefts all along the blade? Thank you.

@Nagakin Thanks for the tip. Since the cerax are a porous soaking stone, would the baking soda permeate and crystalize within the stone during the soak/dry cycle?

Here's a picture of the finish in the morning.

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Looking at it in bright light, I realize I need to be more consistent. Some of it is lighting, but I need to do a better job getting all the way up the kireha/bladeroad with the hamaguri curvature. The left side is a lot more even than the right side.

I would also like more contrast, but this finish is a lot more matte than previously. I am very pleased that the scratches are well-hidden.


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Thanks,
NKW
:dancingcow:
 
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Cerax 3k. More of the same. I have a hunch the left side polishes a lot easier than the right side. I have no idea why that is, but I don't get nearly as much streaking as on the right kireha.

Maybe the left bevel is flatter? Left side bevels are often made at a shallower angle and end up less convex, at least in my experience. I don’t remember if you were trying to keep some convexity here.
 
Maybe the left bevel is flatter? Left side bevels are often made at a shallower angle and end up less convex, at least in my experience. I don’t remember if you were trying to keep some convexity here.

I was indeed trying to keep things a bit more convex, but what you say does make sense.

Why is that? In any case, I will have to do a better job of keeping things even on the right side.
 
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