How to Thin a Japanese Knife: Make it Cut Like New

[@alejandromacouzet7891]

Thank you so much for this video, I always had the sensation that some of my older knifes were not as good as they were when I bought them, even when I thought my sharpening technic is not that bad. I never heard about thinning knifes and it is not something everyone talks about, and to know it changes my whole world haha. Again, this was very educational and really appreciate your time to explain it so nice.

[@KnifewearKnives]

I'm glad I could help!

[@multimanfail]

I think you have the best and easiest to consume knife thinning videos, i would really like to see you continue the polish to a mirror polish though, there arent many videos and even fewer watchable ones. i want to thin my knife but i want to get a really good finishing

[@KnifewearKnives]

Thank you! We don't do mirror polished very often, but we'll make it happen one of these days.

[@multimanfail]

@@KnifewearKnives I understand, its a lot of work and scratches will shine, but there are so few guides too. your attention to detail in these videos have been great so I'll look forward to learning more :)

[@GrantHendrick]

Thank you Naoto for another helpful video. For me the hardest part is feeling the angle that is already on the edge. I basically make my best effort and then sharpen at angle that seems comfortable and that I can keep consistent.

[@KnifewearKnives]

I think everyone struggles with that a bit! Doing a regular visual inspected to tell where you're grinding is a good way to check your work and tell if you need to adjust. Happy sharpening Grant!

[@Guenounovitch]

My favorite videos to watch 🧘🏻‍♀️

[@KnifewearKnives]

Thank you!

[@jimt1575]

Great video!! Thank you.

[@gordonthompson271]

Great video Nuato and certainly one of your best. Sometime it would be interesting seeing how you interact technically with one of the guided systems like the TFPROF. They have an accessory for convex work but I don’t have it.

[@InFuRYoCiTY]

I’d like to watch a video detailing the size of a knifes bevel/cutting edge

[@FunkAndFluff]

5:59 Flat and convex primary bevels are somewhat straightforward. How do you recommend sharpening kitchen knives with concave primary bevels? I'm starting to sharpen for friends and want to make sure I'm doing their knives justice. Solid guide as usual!

[@KnifewearKnives]

Great question! It's tough for sure, as convex bevels are usually done with vertical sharpening wheels or sanders. If you're using stones, softer stones will maintain the bevel shape more than hard stones.

[@ratton5028]

Thanks for the video! Another good educational video. Please keep them coming!

[@KnifewearKnives]

We will, thank you!

[@ijzersterk66]

Thanks for the clear and inspirational explanation! 🤩 I have also been using Naniwa sharpening stones with different roughnesses for my Japanese santoku knife (Shiki VG10 damascus) for 12 years. Functions perfectly. However, I find it difficult to sharpen serious burrs with a 220 sharpening stone. I have a diamond sharpening stone for this. However, the risk of damage is also greater: I have less control over my knife when sharpening on such a coarse stone. Do you perhaps have any suggestions for me?

[@KnifewearKnives]

Hey, do you mean you have trouble raising a burr on 220? Generally I don't find any issues with that stone, but some stones can become glazed and not grind as well. Perhaps try trying the surface with a coarse stone, and see if that works! Otherwise a higher quality stone with more abrasive would likely work better.

[@ijzersterk66]

…yes, that could be the problem. I will immediately put your advice into practice. Many thanks for the quick response and please continue to share your knowledge with us here! 😀👍🏻

[@Foodie-yj1qe]

Thank you for the awesome content! I’ve been binge watching ALL your videos and I can’t get enough. I have a question I’d like to ask if possible. I have a Zwilling 8 inch Chef’s knife. 1. It has a 15 inch angle. Is this considered a Japanese style knife due to its angle or is this still a German knife because of its material? 2. With knife sharpening, I use the 15 degree spine attachment to maintain a consistent edge. However, for blade thinning, which degree attachment can I use? And if there aren’t attachments for blade thinning (as there are for edge thinning), wouldn’t this process ruin the edge I’ve worked to create? And lastly, which should process should be first: blade or edge thinning? 3. How often should the blade thinning process happen? I sharpen my knife on a whetstone twice a year and use a ceramic honing rod in between. Thanks a million:)

[@geoffrobson2493]

Hey! For these sharpening and thinning videos… or… all videos… it would be awesome if you included a list of equipment and supplies in the video description… I love watching the videos through and picking up on the methods and techniques… but it would be super helpful to be able to check back to the video description for the stones used for these at a quicker glance Thanks for all the fantastic knife content - keep it up!

[@graysonziegler4414]

If you hover/click, there's a little button in the corner of the video that says "view products." That's what you're looking for.

[@geoffrobson2493]

@@graysonziegler4414 cheers - thank you - I watch on my smart Tv - so I miss some of those features.

[@graysonziegler4414]

@@geoffrobson2493 cheers!

[@teiaperigosa]

what is the grit # of the Atoma flattening diamond plate?

[@KnifewearKnives]

It's 140 grit! knifewear.com/products/atoma-diamond-plate-140-grit-210x75x2mm?_pos=1&_psq=atoma&_ss=e&_v=1.0

[@Lancelot1992]

I'm still waiting for the shibata koutetsu to be available on your shop. Maybe you can make a Shibata kotetsu review video

[@DAVIDROSS-gl3jz]

Great video but it would help if could put some arrow graphics pointing to the changes made to the knife as I had trouble seeing the changes. Maybe it was the light direction.

[@KnifewearKnives]

Absolutely, we'll definitely do so in future!

[@LouisLumaca]

Dear Naoto, i am quite new to Japanese knives. I feel like heaven that the knife-world opened up to me and since then im a little bit obsessed with everything which has to do with it. So it makes sense that Im addicted to your KnifeWear KZbin-Channel now. I will buy my next Knife definitely from your shops. Hopefully you ship to Germany. (; Thank you for all of your very good output! I have Question regarding of thinning Knife: I Have a Shiro Kamo 140mm VG10 Ko-Bunka and it does not have a primary and secondary Bevel. It's just one bevel from spine to edge. As There is no primary Bevel to thin, do you thin the whole blade or does it make sense to attach a primary bevel to the knife? Kind Regard from Germany, Lo

[@KnifewearKnives]

Hey, glad to hear it! We will be making a video this year about thinning knives with no primary bevel. You can either set a bevel, or grind a more convex bevel that blends into the current bevel, it's up to you! We do ship to Germany!

[@LouisLumaca]

Thank u for the quick answer. Im looking forward to the video.@@KnifewearKnives

[@swedenevguru8483]

So you do the micro bevel with 1000 grit then 3000 grit ?

[@KnifewearKnives]

Yeah! Or 800 and 8,000, you can experiment and find a combination you like!

[@miguel154525]

I’d be nice to see how to sharpen tips and heels. Those often chip or get bent.

[@stvekiz9916]

Hey, i dont have 220 grit whetstone like yours, but i have 400 grit whetstone. Is it okay if i use it?

[@KnifewearKnives]

Absolutely!

[@danielbottner7700]

In my testing... the higher the polish on the bevels behind the cutting edge the more likely the food is to stick to the knife. Sharp 220 Grit seems to provide good food release. How can some of the 220 grit texture be maintained when polishing beyond that point ? Which thinning blade grind angle or angles do you find cooks/chefs like best ?

[@thorwaldjohanson2526]

Food stick is mostly impacted by the profile. A flat grind will have tons of food stick. A convex grind or even s-grind if you have a great maker, significantly reduces food stick. So I would be careful thinning a blade that has one of the more complicated grinds that are better in food release.

[@KnifewearKnives]

If you'd like to keep some texture, you could focus your pressure along the edge on 1,000 grit, as to only polish the core steel. As the other commenter pointed out, the shape of the bevel impacts food separation much more than anything else. Sharpening your knife with a more convex bevel or a slightly higher bevel angle should help! That said, everyone has a different preference.

[@thorwaldjohanson2526]

@@KnifewearKnives have you thinned blades with such a grind? It seems very difficult to me to accomplish that with flat stones.

[@danielbottner7700]

Tested the convex & "S" grinds; they have better food release characteristics, but create other performance issues. Convex & "S" grinds yield more metal creating thicker/steeper wedge angles, which are harder to push through high density foods. Increases in blade thickness of as little as 0.004" to 0.005" ( roughly the thickness a piece of copy paper) make significant differences in the power required to cut high density foods. Finishing at 220 grit provides good food release... even on flat bevel grinds, but blades tend to corrode in the valleys. I appreciatie the ideas shared here in the comments, they help us avoid many mistakes we would otherwise make. @@thorwaldjohanson2526

[@JohnHennigar]

I would like to see a Takada sharpening video please.

[@KnifewearKnives]

We'll have one out in the next few months! For now, this livestream is long but has a ton of good info: kzbin.infoPU4RiED_HW8?si=CyzBnqITeKmZUO59

[@louis2p]

Hey, I always wonder, how would you do it to thin a flat grind knife with damascus clading without ruining it ? You would need some acid to make the patern show again or ?

[@TheDonDada-pn2bg]

You don’t have to thin the whole knife; you can always thin a couple mm behind the knife beveled edge it might change the grind a little but you will leave the pattern untouched

[@KnifewearKnives]

Hey, it depends on the finish. You can either acid etch or use polishing compounds. Shoot an email to hello @knifewear.com and we can help more!

[@louis2p]

@@TheDonDada-pn2bg well the patern kinda cover the entire knife on my YOSHIMI KATO VG10 NICKEL DAMASCUS WESTERN bunka. If it grind it becomes shiny or at least loses the finish on it.

[@rais3tong]

how do i know when do my knifes needs thinning?

[@KnifewearKnives]

You'll find it starts to cut denser ingredients poorly, or it doesn't stay sharp as long as it should!

[@rais3tong]

@@KnifewearKnives thank you so much your awesome 🙏🏻🙏🏻🙌🏻

[@PalmettoPrecision]

Who is making the pink 220 for you guys?

[@KnifewearKnives]

That would be Naniwa!

[@michelepalermo2949]

Sorry but if i have bevel and i don't want to ruin my knife mimetic or design what I have to do?

[@KnifewearKnives]

As far as keeping the original geometry of the bevel? Your best bet is to do regular visual checks to ensure you're grinding the whole bevel rather than just part of it. You could even cover it in sharpie to make it super obvious where you're grinding!

[@michelepalermo2949]

@@KnifewearKnives yeah I mea you said that if there's a primary bevel we should go flat on the stone right? But then aren't we going to damage even the finishing touches Of the blade ? Creating scratches and dullness ?

[@biscuitkitchentknives]

thinning is kinda the easy part, making it pretty afterwards is the hard part.

[@KnifewearKnives]

Absolutely!

[@Revelation_Overland]

Seems like the $300 knife that you buy to cut vegetables would already be the perfect thinness. I’m not sure why this is necessary. Please enlighten me.

[@KnifewearKnives]

Good question! It's not necessary when the knife is new, but as you sharpen the edge and grind away steel, the blade gets thicker. Thinning regularly helps keep the thinness of the bevel that the knife has when it's new.

[@Revelation_Overland]

@@KnifewearKnives thank you

[@michaeltaylor8835]

most knives are poor quality

[@michelepalermo2949]

Oke

[@alanevery215]

Do you think that writing without punctuation is acceptable? If so why should I be expected to make the effort to read It? It is lazy, rude, sloppy and childish!

[@myownbiggestfan]

"Do you think that writing(extra space) punctuation is acceptable? If so(,) why should I be expected to make the effort(extra space) to read it?(extra space) It is lazy, rude, sloppy,(oxford commas are useful) and childish!" There, fixed it for you.

[@MBR843]

Do you think it'll ever be necessary to thin a Shibata Kotetsu kiritsuke SG2? Its already pretty thin to start with but the scratches that comes with the thinning would drive me insane. Thanks

[@KnifewearKnives]

Good question! Eventually, yes. Even a knife that thin needs thinning eventually. If you bring it to us, we can do our best to bring it back to the original finish! We have belt sanders that help create a very even finish.

[@swingbelly]

I am amused by your phrase "building a foundation" when in essense you are removing the existing profile foundation by removing metal. Perhaps, reprofiling the bevel would be more aporopriate. Wonder whether the knife maker would not have thought of this during manufacture.

[@REAPER3fitty]

It is the foundation of the thinning process. It's very appropriate.

[@levskitoronto]

Thinning can be done due to many reasons. One being mentioned is the use and repeated sharpenings, secondly, maybe the maker initially made it thicker so it can be stronger but you are looking for performance, so you thin it. Many of these Japanese knives are hand made, so maybe the sharpener missed a spot... Many reasons to thin, but thinning is more advanced than sharpening and refinishing is more advanced than thinning.