Help with jnats polishing

[mozg31337]

Hello everyone,

I have been trying to polish a Swedish steel yanagiba with a few jnats that I have. I've tried a Chu Nagura as well as Uchigumori bench stones and I had pretty poor results. The soft cladding looks very uneven as you can see from the pictures. I was aiming to make a smooth kasumi finish on the cladding. I was wondering if you could help me to identify the problem with my technique.

Prior to polishing on jnats the blade was done on a 3K synthetic. So, I've flattened the jnats stones and started with the Chu Nagura. Created some slurry with Atoma 400 stone and started polishing with low to low-medium pressure with short length strokes.

After a short while I've started getting feedback from the stones that the blade kind of skips the surface. Tried varying the pressure, but the skipping was still there.

Here are the pictures.




Does anyone know what I am doing wrong? Any suggestions?

 

[Heckel7302]

@milangravier did a very nice Instagram Live earlier this week that talks a lot about how to prep with synths before moving to naturals. Well worth a watch

 

[Bico Doce]

Typically the harder the finishing stone the less forgiving it is to a poorly prepped surface. You’re unintentionally burnishing the cladding with the jnats. If you are going slow with light pressure and your angle is good then it should not be doing that. You are going to need to drop back down to coarse synthetics and get your bevels right first, think 400 not 3k grit to prep that surface

 

[cotedupy]

After a short while I've started getting feedback from the stones that the blade kind of skips the surface.

If I'm understanding your description right - this is what you want to avoid. That's when you're getting the burnishing that BD mentioned above.

Less pressure and thicker mud / slurry should sort the problem (hopefully!)

 

[enchappo]

@milangravier did a very nice Instagram Live earlier this week that talks a lot about how to prep with synths before moving to naturals. Well worth a watch

Came here to post this! I found this video incredibly helpful. It’s long (nearly 2hrs!), but really worth it if you can find the time IMO

 

[Heckel7302]

Another good one from Milan from a couple months ago. You see how long he spends on the 1k to make sure the bevel is smooth before moving up. With polishing, most of the work is done on synths to get a clean bevel. Clean meaning no facets that will burnish on harder naturals, not just scratches.

 

[milangravier]

Yes the problem here is mostly about the bevel shape which is not smoothed, clean, even enough to accep a fine stone like a mikawa nagura and uchigumori.
1. if you don't want to work the all blade and just want the finish : you can work with you 3k, nagura and uchigumori, being concentrate only on the hard steel to make it very clean and good looking, then work with uchigumori and make mud with it with mid/high pressure, then when you have a good amount of mud (polishing paste) just lower the pressure and slow down. In the end, take some finger stones and work the iron with it. You should get a kasumi. (But not a even shaped bevel)
2. You want an even shaped bevel : go back to 400 at least and shape your bevel, meaning first correcting the big low spots if there is, second, work the different parts and the high spots (the heel between facets) to make surface even and smooth. You should get with your 3k synthetic an overall nice finish. If the 3k synthetic give you a messy finish, don't expect to be better with a uchigumori.

I have put most of my lives (yes long videos sorry) on Youtube now, here is another one about shaping :

 

[mozg31337]

Wow, many thanks for your replies and suggestions. I've got some homework to do I guess! Will let you know the outcome

 

[mozg31337]

Yes the problem here is mostly about the bevel shape which is not smoothed, clean, even enough to accep a fine stone like a mikawa nagura and uchigumori.
1. if you don't want to work the all blade and just want the finish : you can work with you 3k, nagura and uchigumori, being concentrate only on the hard steel to make it very clean and good looking, then work with uchigumori and make mud with it with mid/high pressure, then when you have a good amount of mud (polishing paste) just lower the pressure and slow down. In the end, take some finger stones and work the iron with it. You should get a kasumi. (But not a even shaped bevel)
2. You want an even shaped bevel : go back to 400 at least and shape your bevel, meaning first correcting the big low spots if there is, second, work the different parts and the high spots (the heel between facets) to make surface even and smooth. You should get with your 3k synthetic an overall nice finish. If the 3k synthetic give you a messy finish, don't expect to be better with a uchigumori.

I have put most of my lives (yes long videos sorry) on Youtube now, here is another one about shaping :

Thanks Milan for the videos! They are awesome and very informative indeed.

A question on the yanagiba bevels. What technique would you use to create the bevel, considering that the traditional way is to create a rounded bevel with a tiny microbevel at the cutting edge. How would you go around polishing a none flat bevel?

More mud with very low pressure? Also, would you suggest building up the mud with a diamond stone, like atoma 140 or 400 or would you do the mud with the blade at higher pressure?

 

[ReiHamono]

There should be no slurry on nagura when using it for finishing and it should be well soaked in very warm water. Make sure it’s been thoroughly roughed up and then rinse it completely clean and then you want to make sure that all of the edges on the stone have been softened with a smooth object.

If your uchigamori is hard you will have to do the same.

After this you can use finger stones to fix any mistakes.

Spend more time on each stone and report back with pictures from one stone at a time

 

[milangravier]

Thanks Milan for the videos! They are awesome and very informative indeed.

A question on the yanagiba bevels. What technique would you use to create the bevel, considering that the traditional way is to create a rounded bevel with a tiny microbevel at the cutting edge. How would you go around polishing a none flat bevel?

More mud with very low pressure? Also, would you suggest building up the mud with a diamond stone, like atoma 140 or 400 or would you do the mud with the blade at higher pressure?

On the video about stone shaping, you have some information about that.
If you want to shape a convex bevel, there is no real link with mud or pressure, it is really about taking you 400 grit stone (at least) and shape some convexity on your bevel. I would advise to work the bevel with a flat area along shinogi and then work a convexity toward the edge. Then blend those two surfaces. If you have a look on my video about shaping bevels, you should have some information to start with.

If the last question is not related to the shape of the bevel : if you want an easy way to make kasumi : yes, more mud and low pressure is the way. You can indeed create mud with your diamond plate 140 or 400 (try both you may like one more than the other for that case), just be careful about grit contamination. You can also do high pressure on the stone to create the mud, that is possible on a soft stone, it is not really possible on a harder stone, you will scratch your bevel my grabbing the iron.

In that subject, I am happy to help, but there is no handbook really to follow, you need to experience it, you need to practice. Try things. Try atoma 140 on the stone, try without, etc..
If you want only quick way, no brainer, clean the hardsteel with you 3k, clean it again with the uchi using mud created by atoma, then fingerstones.

 

[kman94]

Hey Mozg! So I've been struggling with the same issue for a while now. Only recently has it started clicking. After watching Milan's video and other coaching, you start to realize how important the pre polishing is. As stated, getting an even bevel on the 400 is key. The hard stones like a naniwa pro 3k help to show the mistakes you've made aka the burnishing. I agree with said above, you have to play around with different methods to start to understand what works.

I found I struggled a lot and became frustrated trying to learn on very convex bevels like a deba. It might be good to go to something like a short nakiri and try and make the bevels very flat to polish to get the hang of it.

For a hamaguri, or convex bevel on yanagiba, I had a friend show me a technique where he separates the bevel into 5 sections. Starting at the hard steel as point 1, then lowering angle a little to point 2 (still on hard steel just more shallow). Then touching shinogi as point 3, and finally rocking a 4th and 5th point back to the hard steel. It's hard to get used to, but works well. When Jon at JKI explains it, he does three different lines, then blends. The blending is especially hard as you move towards the tip because it is not only convex from shinogi down, but also from heel to tip.

 

[mozg31337]

Hello again. Some update in my journey into learning polishing techniques and working on this particular yanagiba.

So, after watching a few of Marvel's videos on the bevel I went back to the 3K synthetic stone to polish the hard steel as well as remove a few deeper scratches that came about from trying a soft small kiita nagura stone which occasionally spews some toxic particles. Prior to making this thread I've tried working on the bevel with some fingerstones. Here is the outcome, which is by no means perfect , but a reasonable attempt at making a kasumi finish. Picture 1.

The second picture is working on the 3K Naniwa Pro. Ive learned that the bevel is indeed far from perfect as Marvel was showing with plenty examples in his videos and as several of you have pointed out.

I am not planning to go back to the low grit on this knife and correct the bevel, but instead I will cheat somewhat at the final stage with the fingerstones.

After the 3K I decided to get my 6K out to play with. Picture 3 shows the results. It has removed the 3K scratches pretty well and polished the core even more. I like this stone!

However, the uneven bevel is still very visible despite me working with low pressure and plenty of slurry. Could this stone be hard for an even finish?

Next I got my Chu Nagura. Its a fast cutting stone. I wish it was bigger in size as its not very easy to work with. Perhaps I should create a slurry on a razor hard stone and work with it this way. More experiments to come. Anyways, I've learned that my Chu Nagura is less than 6K grit as there were more scratches on the bevel vs the 6K. My guess is that it's around 4-5K. I have also got a bit more contrast on the bevel, but no where near to what I was expecting from the Chu. I tried a few different approaches , but didn't take the pictures with all of them. The last picture shows the results after I've generated a ton of slurry with 400 grit diamond plate and worked on it with medium length strokes with low pressure. A better result than the 6K with a little less burnishes, but far from a half decent kasumi finish.

The more consistent outcome was with very short strokes and little pressure. Also nowhere near to the fingerstones, but far better than what I have achieved so far on the stones. Will be experimenting more on the Uchi with plenty of slurry and shorter strokes.

Will keep you posted.

 

[KasumiJLA]

What I found in my polishing journey so far is this:

Coarse stone are unfortunately the most important one
It's not fun and it's tedious. I never heard someone saying "yay I'm gonna find some low spots with my 200 grit!" But if the work is not done well on the first stones, the final result will never be optimal. Now I treat each stone to have a visual as if it was the last I use. @milangravier is right, the bevel shaping is super important.

There is no shortcut
In the past I tried to find a way, a technique or to cheat. But it doesn't exist! You have to take the time to do things right. I've already said to myself "I'm going to correct the defect I see on the next stone" or "I'm going to raise my angle a little to find the little missing spot near the shinogi line". These are always false good ideas.

Knowing what your stone can do
I'm talking about jnat here. Even if you have a hard suita or a soft uchigumori, you can manage to have different results with different technique. You can for example burnish your softer stone to reach higher polishing and details. On the other hand you can raise a good amount of slurry and mute the polishing effect by adding contrast/haziness on a harder stone. With that in mind you can understand better how your stones can behave.

The power of finger stone
It's not true that 100% of the most beautiful polishes you've seen are entirely done on bench stone. It's possible, don't get me wrong, but the finger stones are really useful and practical to homogenize everything. It's a wonderful tool that can bring an "ok" finish to a really nice one. The fingerstones love you and you want to love the fingerstones.

You have to have fun
If you are in a bad mood and nothing is going well with your polishing session, stop everything! For real. How many times I wanted to continue because I absolutely wanted to achieve perfection despite everything going wrong. For me polishing is my moment of relaxation. Once a month I even have to take a forced break to refuel. When I start again, everything is always better and I learn twice as fast as by struggling.

Don't compare yourself to others
I'm new here but I've been looking at everything here on this forum for three years. How many times have I thought to myself that this @nutmeg makes my polish look like I threw my knife in a pile of gravel!? I no longer compare myself to him, I am inspired by him now! Everyone started somewhere and everyone had disgusting results! This is the principle of learning. Allow yourself the luxury of making mistakes, understanding them, approaching with a new vision and moving forward in your process.

 

[Steampunk]

What I found in my polishing journey so far is this:

Coarse stone are unfortunately the most important one
It's not fun and it's tedious. I never heard someone saying "yay I'm gonna find some low spots with my 200 grit!" But if the work is not done well on the first stones, the final result will never be optimal. Now I treat each stone to have a visual as if it was the last I use. @milangravier is right, the bevel shaping is super important.

There is no shortcut
In the past I tried to find a way, a technique or to cheat. But it doesn't exist! You have to take the time to do things right. I've already said to myself "I'm going to correct the defect I see on the next stone" or "I'm going to raise my angle a little to find the little missing spot near the shinogi line". These are always false good ideas.

Knowing what your stone can do
I'm talking about jnat here. Even if you have a hard suita or a soft uchigumori, you can manage to have different results with different technique. You can for example burnish your softer stone to reach higher polishing and details. On the other hand you can raise a good amount of slurry and mute the polishing effect by adding contrast/haziness on a harder stone. With that in mind you can understand better how your stones can behave.

The power of finger stone
It's not true that 100% of the most beautiful polishes you've seen are entirely done on bench stone. It's possible, don't get me wrong, but the finger stones are really useful and practical to homogenize everything. It's a wonderful tool that can bring an "ok" finish to a really nice one. The fingerstones love you and you want to love the fingerstones.

You have to have fun
If you are in a bad mood and nothing is going well with your polishing session, stop everything! For real. How many times I wanted to continue because I absolutely wanted to achieve perfection despite everything going wrong. For me polishing is my moment of relaxation. Once a month I even have to take a forced break to refuel. When I start again, everything is always better and I learn twice as fast as by struggling.

Don't compare yourself to others
I'm new here but I've been looking at everything here on this forum for three years. How many times have I thought to myself that this @nutmeg makes my polish look like I threw my knife in a pile of gravel!? I no longer compare myself to him, I am inspired by him now! Everyone started somewhere and everyone had disgusting results! This is the principle of learning. Allow yourself the luxury of making mistakes, understanding them, approaching with a new vision and moving forward in your process.

100% Yes... This is spot-on. This should be a sticky, for all those who are trying to perfect their polishing. Organized, concise, relatable, accurate... A perfect primer.

 

[KasumiJLA]

100% Yes... This is spot-on. This should be a sticky, for all those who are trying to perfect their polishing. Organized, concise, relatable, accurate... A perfect primer.

Thank you sir! Honestly I had so much fun writing this!

I took the time to remember how frustrating it can be at the very beginning. My first real bench stone was from Otto (@Badgertooth), a beautiful Maruoyama Aisa. He had shown me an example of finishing on a gyuto and I was immediately charmed. A hazy Jigane with a bit of reflection combined with a frosty hagane with lots of sparkle. But when the stone arrived at my house, this magic kasumi of Otto simply did not exist. And it was so frustrating!

So yeah, I learned a lot and still learn a lot. I'm a much better polisher than 3 years ago but I know I still have a thousand things to learn. That's the beauty of this passion

 

[enchappo]

100% Yes... This is spot-on. This should be a sticky, for all those who are trying to perfect their polishing. Organized, concise, relatable, accurate... A perfect primer.

Couldn’t agree more!

Great post @KasumiJLA

 

[mozg31337]

Great posts guys. Gives me courage and inspiration to continue learning this tricky business

 

[KasumiJLA]

Couldn’t agree more!

Great post @KasumiJLA

Thank you sir!

Great posts guys. Gives me courage and inspiration to continue learning this tricky business

Oh yeah, don’t give up man. For real! You’ll be hooked on your first good polish