Flat to Convex and Final Rough Sharpening on 400-800 Grit - part 2 | ハマグリ刃の研ぎ方

[@alex-loxa]

Very informative explanation. I’m happy to get such great advices.

[@kevintran3158]

Love that your explanations are getting more clear and we progress videos.

[@laforgeduronin1597]

Thanks for this video sifu 🙏🙂 help me a lot for my forged knives to step up again

[@thiago.assumpcao]

Food adhesion happens because of capillary adhesion effect, less surface contact area means less sticking. The overall geometry for Japanese knives take this into account and even their Flat Grind already offers protection because of the shinogi line. Their design is so much better than a western Full Flat Grind. S Grind, hammered finish and irregular surface from the kurouchi also helps avoid food sticking.

[@Yupppi]

Really really fascinating when you go in-depth on the whole thought process of how you decide on the way to approach and execute the plan. I believe it really helps people who try to become better at sharpening, to move from having technique to having a good strategy. And what I find particularly helpful is that you don't show just different geometries and why something is good, but the context and how to go about with an existing item and geometry. Like how to actually make what you want for a result. People often warn you about not doing a straight push/pull on the whetstone to avoid rounding the edge and killing the sharpness. Which is why in my head convex geometry seems extra difficult to sharpen. However this method seems approachable. I have already tried (with Ivan's and Murray Carter's techniques) with a cheap kitchen knife to straighten it out and create two distinct bevels and thinning out the knife and it really helped in understanding the process and performance, to be able to actually see what your work is doing and to get the basis for sharpening, the pre-sharpening process, in a better place. The scratch direction change is also really helpful for observing the effects. Now I've maintained a better and smoother cutting performance than I've ever had for a good while, so I'm very happy with the lessons. Btw NSK seems to be picking up recognition here in the west as well as your videos with their stones are getting published. My go to sharpening tools entrepreneur just added a category for upcoming NSK products in his catalogue. And he tends to have a pretty long trial period before he decides on a new brand and which products to introduce in his small shop, so seems like NSK has made an impression.

[@ivanyuka-japan]

Thanks so much for the great insight into my work, I often try to approach sharpening in two ways primarily what the blacksmith intended and how or who will be using the knife. From here I go onto piecing together a plan of approach.

[@La_sombra_de_la_luz]

El más interesante de toda la serie. Mil gracias por tu tiempo y mostrarnos tu conocimiento. 🎁❤

[@LtKwasretaken]

Thank you for going so in-depth. Very informative and helpful, and well presented.

[@scharfermax]

Another invaluable demonstration of the art of sharpening! Thank you, Ivan, for these clear and well-illustrated explanations! It seems to me that the information at 18" is particularly important, but personally, I didn't understand the connection between the 200 and 400 scratches... Perhaps there will be additional information in the following parts?? Also, the question of the pressure to exert during the different stages of making the hamaguri: Would it be possible to have an idea of what pressure is being referred to, and if it's measurable or just based on feeling? Is a strategy with a marker drawing a solution for working precisely when one doesn't yet have the required experience? Thanks again and nice hommage to Morihiro!

[@ivanyuka-japan]

Thanks I’ll go into more detail about this in the next video

[@scharfermax]

Thanks, Ivan! Looking for to learning more about it!

[@lunfardo]

Great video anyone curious about polishing should watch. Would be great if at some point you could walk through how exactly you ensure a uniform polish across the curved surface

[@ivanyuka-japan]

Thanks, we will include this in the next few videos

[@TheMegalegenden]

This type of content is wonderful ❤ more of this :)

[@josemartins5207]

I would love if you could put where we can buy the same natural japanese stone you use 🙏

[@ivanyuka-japan]

Hi thanks ! Most of my stones are from various stone shops in Kyoto where we live

[@revilolavinruf]

Great vid!

[@sanduliaka]

Thank you!

[@AKBoost]

Nice work!

[@yaniv5055]

Thx for this great video Ivan super informative 🖤🔪🎶🍻🎶

[@omfgbbqsauce1177]

So, to cut the convex bevel, you didn't change the angle by raising the blade, but just pressed harder along the edge? I don't really get how you actually ground that initial 400 grit hamaguri :(

[@ivanyuka-japan]

Hello The area that is along the edge I used more pressure at the 200 grit stone, this added pressure in the right place, at 200 grit the area wears evenly along the edge making essentially very subtle change in angle, then when I go to the 400 stones in the same area adding a bit of angle change I get a very subtle hamaguri. I hope this makes sense it’s difficult to explain in worlds

[@jjshane72]

can you guys can maybe invest in a clip-on-mic to improve audio quality? I really enjoy watching and listening to your videos while I work or do other things but sometimes Ivan's voice is a bit too quiet

[@ivanyuka-japan]

Thank you for watching while you work! Sound has always been an issue for us as well, and while it's much better now that we have a Sony external mic, we'll look into getting a clip mic as well.

[@jjshane72]

​@@ivanyuka-japanI enjoy watching your videos as I work on my own knives and try/practice different techniques, your videos has helped me a lot but since I like to work without headphones on so sometimes your voice gets a bit quiet 😅

[@jjshane72]

​@@ivanyuka-japanalso I've heard that a good way to blend the 2 bevels is with a rocking motion and soft stones at the point where the 2 bevels meet, is this a good way to do the blending?

[@junior90210]

Phenomenal video! What's the angle at the apex?

[@ivanyuka-japan]

Finally confirmed the angle, it's around 12 degrees

[@paweel2494]