To get the concave grind, it looks obvious (but we could be totally wrong) they allow for extra maybe 1mm-2mm thickness on the flat side, do the hollow grind all the way up to the tip/edges, and then thin it by grinding the flat side, resulting in a frypan shape and a very even hollow. Only say obvious because we use yanagibas as fishmongers a lot and the hollow runs all the way until almost the tip.
@bahur472 жыл бұрын
now I understand why they say the honyaki is much harder than the laminated blade. When it's laminated you can tweak it any time with a bit of bending , and with a piece of mono steel you just have to be perfect. Very interesting and helpful video , thank you for documenting and sharing your learning process.
@_jaeger_fabian2 жыл бұрын
I'm super duper excited! Can't wait for it 😱 I'm curious how you make the Ura. 💪
@SzyMoc_2 жыл бұрын
Awesome video man, it really helped me understand single bevels. Time to practice ura grinding some more :>
@AbidAmeedZA2 жыл бұрын
A couple of South African grinder manufacturers have table that sit under the wheel which allows you to use the table as a work rest and also to see what you're grinding. That setup might help you with the Ura.
@DonNguyenKnives2 жыл бұрын
That definitely makes sense! A work rest around that area would make things more stable too, if you rest your hands on it
@alexfletcher9652 жыл бұрын
You talking about the Herbst ultimate??
@wesleykeudel-schaffer76752 жыл бұрын
I'd also recommend using water on your belt so you can work closer to the edge...
@cameronallen99482 жыл бұрын
Don just spitballing here but what about using a radiused platen to get the middle section done, then a smaller wheel like you have, or maybe in 4 inches to get the edge and spine then going back to something like a felt radius platen to blend it? all while using a pivoting work rest that's not too wide (like as wide as the belt) so you can pivot the knife as you get towards the tip. Edit: I'm just now realizing we have no idea how "in the past" this video is and you may already have a solution
@just_don_things2 жыл бұрын
That's a good approach for sure, and it's similar to the one I currently do right now. I DEFINITELY thought a lot about work rests and designs to be able to pivot the knife. I think it would work if designed really well
@_jaeger_fabian2 жыл бұрын
Great video, thanks for sharing your knowledge ✌️ pretty excited about the interview with Jon Broida. Thought I saw it in the past but can't find it anymore 😔
@taiguaraperfetto2 Жыл бұрын
straightening technique on the little hammer by luciano dorneles from Brazil
@just_don_things2 жыл бұрын
First.
@jackcraft30542 жыл бұрын
This is great seeing the process after handling the finished piece at Travis'. Thanks for sharing your process.
@jackcraft30542 жыл бұрын
Also nice shirt. Hung out with she and Chris last weekend.
@user-xt4wu8by4j2 жыл бұрын
日本の庖丁に興味を持っていただき誠に嬉しい限りです! 和包丁の名産地、大阪は堺市に是非行ってみて頂きたいです。 I’m so impressed and happy that you are interested in Japanese knives. I really want you to visit the most famous Japanese knife industry place in Sakai-city in Osaka prefecture. I’m working in a knife shop which is located in Kappabashi in Tokyo so if you ever think of coming to Tokyo, you should visit our shop!
@DonNguyenKnives2 жыл бұрын
That would be amazing! I would love that one day
@Mucidamascusblades2 жыл бұрын
I know by now you already completed the project (I am a bit late on this serie of videos) so I don't know if it will be helpful but in razor making we start the compound grind using a wider radius first to set the bevel width, then we change the wheel cutting the diameter in half for each pass (for example 8", 4", 2"). That gives us crispy lines and a very uniform compound hollow. Granted, razors are a lot smaller and thicker and the hollow is not in the middle of the bevel... thank you for sharing your journey!!
@twocrowsblades35442 жыл бұрын
Heat treat the blade blank before bevel grinding and use Norton blaze ceramic abrasive belts dip in water often each pass keep cool 36g then 50 or 60 grit next 120 can go finer with aluminum oxide or Norton norax belts then cork belt then scotch bright finish belts and if want polished go on to buffer
@thomashackerforgedknives25332 жыл бұрын
Super excited for this!!
@markjo782 жыл бұрын
Hollow ground backsides are seen in high end chisels and knives. It allows the maker and user of the knife to be able to make the backside super flat without having to deal with or grind alot of real estate. You just have to flatten a small surface area to help you make the sharpest edge possible One downside if that if that perimeter gets too narrow from use or sharpened incorrectly then the knife is trash as there is no way to recreate the hollow ground backside once the perimeter is gone....it is impossible to repair The ability to release any suction on the flesh of the fish is also likely important as these knives are specifically made long to be able to cut the fish in one pulling stroke rather then sawing and the decrease resistance to the pulling due to a sharp edge, small surface area contact due to its thin profile and hollow ground all play into the design.
@fencingrocks32 жыл бұрын
There's been a ton of talk on BladeForums about carbide hammers for straightening too. I'll have to try making one too! Thanks for taking the time to put this together and document your process. It's super helpful and interesting!
@noahnipperus73202 жыл бұрын
Another great video (also really good job on keeping the video at Jon Broida's shop consistent visually with video at your shop (like, remote video spots often look fucking blair witch in comparison visually because the lighting is completely different then your staged home lighting rig)) looking forward to ep2!
@Inecendium2 жыл бұрын
Looks like a yanagiba any% there, actually about the warp you have to undestand that they grind it on huge round spinning wetstones wich minimise te warp, in addition to that, they have wooden "platens" that hold the knife in place and baking it up at its fill contour, the compound grind is done just liek you did there, the deep part is horizontal to the wheel and the more shallow and wider part is diagonally to the wet stone. Im taking a guess here but im pretty positive that the grind the hollow part fully, from the spine to the edge but then just put it on sharpening stones to make that flat spot. Also the sick hollow grind also helps to prolong the wetstones life, because theyre not cheap, and never actually were (the natural ones) so in addition to air pocket that was another reason :)) great work keep it up!
@DonNguyenKnives2 жыл бұрын
I wonder if the large waterstone actually helps mitigate warp. For me I've found that warp during grinding occurs through metal removal, rather than heat and force. For an asymmetric grind, I kind of picture it as though I'm taking out strings of tension but only on one side, or something like that. I could be totally wrong but that's been my experience. Jon was actually telling me that for the hollow grind they do it all the way like you said, and then just flatten it on a stone to get the uraoshi, rather than how I'm approaching it which is to "chase" it to the flat section as close as I can.
@Inecendium2 жыл бұрын
Hey don, theyre wetstones are constantly watered that what i thought helps them.. Theres an amasing channel that ive been watching thats a good resource kzfaq.info Hes a real pro, hes mainly resharpening the knives, doesnt make them from scratch but sure hope youll find many helpful things there :)) Waiting for the next parts of the series!
@DonNguyenKnives2 жыл бұрын
@@Inecendium Haha I've definitely watched a lot of his videos to see his technique
@JH_Forgeworks2 жыл бұрын
I've only made two, so take that into consideration. But, in doing my research and comparing, I noticed the same semi-stepped Ura on the back of the blade. I made mine by using a wheel to set the central / deeper ridge. I then followed up with a 36 inch radius platen to bring the Ura closer to the spine and edge creating a full convex on the rear of the blade. I finished and blended/dialed it in by hand with paper and stone to get about 1/16 off the edge and slightly less from the spine. Might not be the perfect way to do it but, it seemed to provide the best overall order of operations in my practice and final attempts. I'm sure you've figured out a better way by now that we'll see in future videos but, thought I'd share just in case.
@DonNguyenKnives2 жыл бұрын
That's just about exactly how I do it now also, interesting we both came to the same process. Mine varies slightly differently as I use a 14" wheel for everything, but same order of operations
@Rsama602 жыл бұрын
Maybe some of my comments might be obsoleted by watching your other videos I made 2 yanigaba in my life (mono steell full py hardened) Knife 1 I could finish successfully. I warped a bit but I could straighted it). I muts admit my ura sucked (I gotvit blended in but not very fine) but I got the knife sharp. Knife 2 warped significantly. It was more like a banana. I tried to straighten it but during that procees it cracked. Knife 3 is in the making, raw blade is shaped and heat treated but no other grinding done yet. About straightening of a warped blade. I made an apprenticeship as a tool aand die maker. Most of thin tool parts came warped out if heat treatment. Before further grinding we straitended them by hammering. We used small ball pen hammers, same principle as a carbide chissel hammer but not as aggressive. As you learned by yourself there is a limit you can fix with this. As for hollow ground. It needs a lot of practice. For my first ura I established a center hollow grind with a smaller wheel then then switched to a curved platen and widended the grind gardually. You are right you can’t see it but with practice you can feel it. As practice try some hollow ground hunting knives. I also made two straight razors, both is a good practice. And I always gring standing, sitting down tenses my body two much and I loose control.
@davidcorn43242 жыл бұрын
Have you tried lapping in the Ura with a wet stone or granite block and sandpaper?
@DonNguyenKnives2 жыл бұрын
I have indeed tried that
@SamMurlless2 жыл бұрын
You Used It!?!
@DonNguyenKnives2 жыл бұрын
I wasn't joking hahahahaha
@Indy1701e2 жыл бұрын
Wouldn't it be easier, to first do the urasuki from edge to edge and then make the edges flat for the uraoshi?
@DonNguyenKnives2 жыл бұрын
Yes, that's you're supposed to do it lol.
@kenos01 Жыл бұрын
That's how it's done.
@krissteel40742 жыл бұрын
I love the unga-bunga caveman hammer! Years ago I got a commission for a Kiritsuke which is basically something I never make out here in the backwoods of Australia. Its got the same sort of weird hollow-compound in the back and single bevel setup. Hmm I thunks to myself, how I into this geometry without making boomerang? So using the greatest western minds which aren't mine, I just grabbed the most dimensional stable billet of steel I had in the whole shed- big ol lump of D6 ledeburitic which is just heaps of carbon, tungsten and chromium that just turns into crazy lumps of carbides to the point its just god-awful to sharpen, but it never really gets blunt either. I think it took 3 x 2h tempers just to get it a bit tougher at 62HRC but it didn't warp! No way in hell even at about 80% done to shape at the air quench it hung in there somehow and all the subsequent grinding after that. Anyway, that's all I've got to add and good luck!
@lbdeuce2 жыл бұрын
There is a pretty good amount of information out there.
@DonNguyenKnives2 жыл бұрын
There is, but I found that it's more surface level stuff, and I wanted to get a bit more technical.
@lbdeuce2 жыл бұрын
@@DonNguyenKnives i can imagine a dearth of info specifically regarding doing traditional knives on modern machinery. so many variables involved when you change the tooling.
@alp77782 жыл бұрын
You‘ll need a bigger hammer 😅 all joking aside, the carbide hammers we use for straightening blades are a lot heavier and you basically just use the weight of the hammer and the bounce of the anvil to set your marks. Think about one kg/ two pounds of weight of the head. You‘ll get marks that you‘ll need to grind out but the effect goes pretty deep…
@DonNguyenKnives2 жыл бұрын
Hahahahaha yeah the "hammer" is a bit.... undersized. It actually works really well for my process now though, I don't think I need it to be any bigger.
@tylermertens19332 жыл бұрын
Super interesting build, and very informative video! I wonder if there is a way of using a mill or CNC to carve out the back of the knife before heat treat?
@DonNguyenKnives2 жыл бұрын
I've thought about that too, and you could definitely do it, but the trouble comes during and after the quench. I think it would be an absolute nightmare to deal with the blade after it's been cnc'd and heat treated
@tylermertens19332 жыл бұрын
Yeah as you mentioned you get a lot of warp during the grinding process. I’m curious about what steel your using? Also does the warp come from the stress being on one side?
@DonNguyenKnives2 жыл бұрын
@@tylermertens1933 I've used W2 and 52100 for these so far. Both have had warping issues
@nelsonchen78232 жыл бұрын
7:30 seems to be the key here, i never seen a mono-steel single bevel knife from japan. i wonder if it will make your life easier if you start here. and japanese smiths definitely grind with jigs on whetstones, i cannot imagine free handing that kind of geometry.
@DonNguyenKnives2 жыл бұрын
They exist, but they're rare, and of course sought after because of how seldom makers do them
@nelsonchen78232 жыл бұрын
@@DonNguyenKnives i bet, seems like they will take much more time, care, and skills to make.
@DonNguyenKnives2 жыл бұрын
@@nelsonchen7823 A laminated construction is definitely a good approach though, and I'm starting to learn how to forge weld stuff so I'll have to try it soon!
@MRSketch092 жыл бұрын
I'm no knife grinding expert... but I have a suggestion, you can take it as a grain of salt.. If you used a press with a "Jig set up".. I.e.. some round stock, that was the right size, that was parallel to the metal being worked, to mash your metal, into the "U" shape, your wanting, BEFORE you start grinding on it, , then you could just gently nudge the metal into the "U" shape your wanting... And then just go to town, removing material.. on your belt grind on the flat part.. That would automatically give you your desired outcome, at least that's how it'd work out in my imagination. So maybe you already thought of this? maybe you didn't? but that's how I'd tackle it... rather than trying to do it AFTER the fact.. Hope this suggestion gets the creative juices flowing for you?
@DonNguyenKnives2 жыл бұрын
I've thought a lot about how to shape that hollow grind a lot, and I think there are a ton of methods you could do before heat treat. The problem is definitely once it's hardened, even if it's completely straight, it will warp as you take material away. In this scenario the ura would be shaped, but then you're limited by that shape being there and you have to do everything around it, and if you ever need to revisit in that hollow area you are screwed.
@MRSketch092 жыл бұрын
@@DonNguyenKnives How do the Japanese do it then? I mean, the way I mentioned, if you used a lot of water/coolant, seems like it would work? that should keep it from warping? I know all the videos where I've seen Japanese sharpening cutlery, they've always had a lot of water flowing.. especially on those "round wet stones" they use.. Anyways, thanks for the response.
@justinwilliams42122 жыл бұрын
how useful do you think a metal scraper would be? say a really hard W2 blade. I think sword makers used them
@bogower42162 жыл бұрын
I was wondering about that too. Also, was wondering if Murray Carter has done any videos on a yanagiba.
@DonNguyenKnives2 жыл бұрын
Can you use those on hardened steel? I thought that would be for pre-heat treat
@DonNguyenKnives2 жыл бұрын
@@nephronmaster1 Ooh interesting, I'm going to pick his brain on that
@twocrowsblades35442 жыл бұрын
Get u a 10 or 14 inch wheel
@lordofgonzo2 жыл бұрын
You're doing the hammering wrong. You hammer to the inside of the warp and the metal spread by the peining corrects the warp. It works because you're hammering on a flat and hard surface, but it's going to keep warping unless you do it correctly. You'd be better off hammering with a mallet on something like a wood block, which shouldn't be as dangerous as hammering on a monosteel blade.