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Post by althesmith on Jan 25, 2019 5:28:58 GMT
Is there any reason besides tradition that artificial stones cannot be used for most stages of sword polishing? Notice I'm not saying anything about personal preference, just whether it's tradition or an actual hard and fast reason. And any reason that "Japanese" waterstones cannot be located elsewhere? I've known of some artisans who have had good success with locally sourced North American stones.
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Post by althesmith on Jan 25, 2019 10:52:38 GMT
An interesting article from a few years back. Amazingly, a Japanese Togishi seeing this man's work and finding he was entirely self-taught, did not rush over and accuse him of "desecrating" or disrespecting Japanese blades/art but shook his hand, complimented him and told him he wished his own students had that level of dedication! ejmas.com/tin/tinart_blain_0203.htmlI find as I spend more and more of my life in the field of blacksmithing/bladesmithing that good craftsmen from any part of the world recognize their brothers in the field no matter what country or continent or tradition they are from.
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Post by RaylonTheDemented on Jan 25, 2019 13:57:55 GMT
Definitely an interesting article, thank you for sharing.
o7
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Post by seraniz on Feb 12, 2019 19:58:08 GMT
Definitely an interesting article, thank you for sharing. An interesting article from a few years back. Amazingly, a Japanese Togishi seeing this man's work and finding he was entirely self-taught, did not rush over and accuse him of "desecrating" or disrespecting Japanese blades/art but shook his hand, complimented him and told him he wished his own students had that level of dedication!
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Post by ArturWroclaw on Feb 21, 2019 20:32:29 GMT
Synthetic: they are safe, predictable, homogeneous, easier to work on.
Natural: there are inclusions of hard factions, rust, harder to work on, but finishing polishing is done with the use of natural stones. Hazuya and jizuya (regarding the polishing of Japanese blades) are made of uchugumori stones, narutaki, nakayama ...
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Post by pvsampson on Feb 22, 2019 0:13:07 GMT
Synthetic: they are safe, predictable, homogeneous, easier to work on. Natural: there are inclusions of hard factions, rust, harder to work on, but finishing polishing is done with the use of natural stones. Hazuya and jizuya (regarding the polishing of Japanese blades) are made of uchugumori stones, narutaki, nakayama ..." Natural Japanese stones can be expensive as well. I use straight razors that I hone myself and Japanese naturals are out of my price range so I use synthetics,but I have had one of my Bengalls honed by a guy that used Japanese stones and the edge was way smoother to shave with.Not sharper though,it just had a different edge to when I use my synths on it. There are sub forums on some wetshaving forums that focus on straights,and it is there that one can find in depth discussions on natural Japanese stones.Very informative for anybody that is interested in the subject.
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Post by ArturWroclaw on Feb 22, 2019 9:04:03 GMT
when you do jihada and then ha, looking for all the effects of hardening, you use natural stones, I have not heard that with synetic stones you could have good effects with it.
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Post by althesmith on Mar 18, 2019 0:45:38 GMT
Namikawa has synthetic Jizuya stones now. Very long lasting and bring up the hamon quite effectively on an old sword without leaving scratches.
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Post by john1 on Mar 19, 2019 0:01:07 GMT
I also hone straight razors - and can attest that the finish left by natural stones is way smoother / less harsh feeling. Basically, the natural stones leave an edge that’s similar to what results after stropping - but without rounding the edge slightly like the flexible surface of a strop does. No idea how if this translates into benefits for a sword edge though.
The finish from a synthetic stone is also much more mirror like. The finish from a natural stone is more hazy. No idea if this translates into making the Hamon more varied looking within the hardened zone, or more dramatically different between the Hamon and the Ji.
My understanding is that both effects for straight razors are caused by the differing grits with the surface of a natural stone. Artificials are extremely uniform.
A Belgium Yellow Coticle will create this effect much cheaper than an Japanese natural. (Approx 10,000 Japanese synthetic equivalent). In the middle (price wise) is an Esher. The blue Belgium stones are a slightly coarser version of the yellows (approx 8000 Japanese synthetic equivalent). In synthetics, I use the 12,000 Japanese grit. It leaves a very mirror like finish and edge that’s too sharp to shave with comfortably (Ie: too harsh). The edge has to be rounded a little with with some .5 micron paste on a strop to shave comfortably. Which also takes away some of the mirror like shine.
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Post by jonessteave on May 3, 2024 14:07:32 GMT
I also hone straight razors - and can attest that the finish left by natural stones is way smoother / less harsh feeling. Basically, the natural stones leave an edge that’s similar to what results after stropping - but without rounding the edge slightly like the flexible surface of a strop does. No idea how if this translates into benefits for a sword edge though. The finish from a synthetic stone is also much more mirror like. The finish from a natural stone is more hazy. No idea if this translates into making the Hamon more varied looking within the hardened zone, or more dramatically different between the Hamon and the Ji. My understanding is that both effects for straight razors are caused by the differing grits with the surface of a natural stone. Artificials are extremely uniform. A Belgium Yellow Coticle will create this effect much cheaper than an Japanese natural. (Approx 10,000 Japanese synthetic equivalent). In the middle (price wise) is an Esher. The blue Belgium stones are a slightly coarser version of the yellows (approx 8000 Japanese synthetic equivalent) Explore gemstone varieties. In synthetics, I use the 12,000 Japanese grit. It leaves a very mirror like finish and edge that’s too sharp to shave with comfortably (Ie: too harsh). The edge has to be rounded a little with with some .5 micron paste on a strop to shave comfortably. Which also takes away some of the mirror like shine. natural stones are preferred for sword polishing due to their unique properties, including varying hardness and abrasive qualities, which result in a refined finish. While tradition plays a role, practical reasons also contribute to this preference. Regarding "Japanese" waterstones, their scarcity outside Japan is mainly due to the specific geological conditions needed for their formation. These stones are sourced from specific quarries in Japan, resulting in stones with desired sharpening characteristics. While some artisans may find success with locally sourced North American stones, they may not replicate the exact qualities of Japanese waterstones, leading to their continued preference among enthusiasts.
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Post by mrstabby on May 3, 2024 15:28:50 GMT
Synthetic stones (like Shapton Korumaku Pro ceramic stones) are more consistent in scratch pattern because they produced with high control over grain size, natural stones will have always bigger grain inclusions, I guess this is why the synthetics will come out more polished than a similar grit natural stone. You would just need to buy a lower grit to get the same finish. They also are much harder and will not need to be flattened as often (if at all because they are made for high abrasion resistance steels, and sword steels are pretty easy going in comparasion). Something else positive about modern synthetics is, that you don't need to soak them. Just dip and go (at least with the Korumaku Pro - don't buy the "Glass" Shapton stones, they will wear much faster on soft steel than the Pro, just FYI). In my opinion it's a combination of tradition and rarity making original japanese Stones so sought after, also if you buy a real Japanese. stone, you know what you'll get.With synths there are very good, but there also are bad ones that cost the same, it's more of a guessing game.
I have never heard too sharp an edge will give a harsh shave, more likely it is a burr. I am also not quite sure about the 0,5µm leaving a hazy finish. 0,5µm compound should give a high mirror polish unless it or the strop is contaminated.
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Post by larason2 on May 4, 2024 3:49:07 GMT
The synthetic stones from Namikawa Heibei will do the job. Except for the uchigumori, no reason to get natural unless you want to vary the aesthetic. The Shapton are great, but I wouldn't use them to try to put a traditional polish on a sword, they just don't have the right properties. They'll do fine sharpening it though. They are great for polishing soft metals like copper, but not so good for steel.
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Post by mrstabby on May 4, 2024 5:52:52 GMT
The synthetic stones from Namikawa Heibei will do the job. Except for the uchigumori, no reason to get natural unless you want to vary the aesthetic. The Shapton are great, but I wouldn't use them to try to put a traditional polish on a sword, they just don't have the right properties. They'll do fine sharpening it though. They are great for polishing soft metals like copper, but not so good for steel. Honest question, why do you feel they are they bad on steel? (I mean I have no experience with original japanese stones) Are they too agressive? EDIT: Wow, they go up to 30000 now, I have never seen a 30000 grit synth stone...
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Post by larason2 on May 4, 2024 17:22:40 GMT
No problem! They just don't reveal the underlying details well. They're so hard, doesn't match up with the hardness of the ji well (usually harder stones good for the ji, softer for the ha, but they're too hard even for the ji). So compared with the Namikawa synths or even natural stones, you just don't get the effect you're looking for easily. It's also difficult to not push too hard if there's a big hardness mismatch, which can cause the steel to burnish. They can sort of work ok, but it's going to take 3x longer than even natural stones, and it's never going to look as nice. Trust me I've tried! On copper though, they polish amazingly well.
Stones are tricky to wrap your brain around, because they really have two hardnesses, hardness of the stone, and hardness of the abrasion. I conceptualize it as the adhesion between grits in the layer, and the adhesion between layers of grits. On synths, these forces are roughly equal, and higher than any natural stone because the grits are more triangular because of how they are produced (so more surface area of adhesion to one another). So hard stones like the Shapton are really quite hard, and it's hard both to cleave off the metal "spikes" on the surface through direct action, and hard to break through the layers via abrasion. The soft namikawa don't abrade directly much, but since they're soft they do break off to abrade well, giving a nice polish. The Shapton though are better for sharpening, which tends to favour direct action more. Natural stones are funny, because their grits are more rounded. So they can get softer than the softest synthetic, but they also take longer than any synthetic, because there are less nooks between the grits for the bits of metal to get caught on. They also tend to have lower adhesion between layers than between grits (because of how sediments are deposited). However, as a stone is compressed in the ground, you can get reversal of this, because linear pressure on the layers tends to fracture them laterally and provide more adhesion between layers. So some natural stones are like synthetic ones, but far more common is to have mismatch. So there's more range, and more likely that if you have lots of stones, one of them is going to be a good match for the hardness of the piece you're polishing or sharpening. If you don't have many though, you may find none of the natural stones you have work! So synthetic stones have more narrow applicability in a way, but it depends on the natura stones you have whether they will be useful. The Shaptons are great, but they are more for grinding than polishing. Awesome for putting an edge on practicaly anything, but not really polishers unless you are using them on soft metals. There's no way to polish a Japanese sword faster than with the Namikawa synthetics, but if you want more range and subtlety to the polish, you have to go natural. The Namikawa can sharpen, but generally it only works well only through abrasion (usually have to go along the length of the edge). So if you set out to polish a sword, often you make it razor sharp without meaning to just because you're abrading the surface right by the edge. They won't make a dull sword sharp, but they will make a sharp sword insanely sharp. Naturals aren't that useful for sharpening unless you're finishing or honing razors, in which case it's easier to find a stone with just the right properties for your shaving preferences (smooth vs toothy). But they have a huge range of aesthetics to the polish (provided you are able to polish a traditional open grain), which is why they are valuable. That being said, there are natural stones that can sharpen, but it's harder to do it, and they generally take longer.
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Post by mrstabby on May 4, 2024 18:31:42 GMT
Yeah, I get it. They are quite sharp toothed so to speak. For knives nowdays you also need somthing hard to get anywhere, and they are primarily for that market, probably not enough demand/money in it to produce good synthetic polishing stones. The Shapton are more like diamond stones in a way, they won't produce much of an emulsion of broken off particles. Under the microscope you can see a difference, how to say this... If the stone does not break up the scratch pattern is more linear, if there is more emulsion it will be more diffuse, like brushed vs satin finish. I have diamond stones and diamond powder, and using a 3000grit stone will leave a much hazier finish than putting some powder on a steel plate with water - even if both are the same grit size and shape. That difference is even more noticeable when the surface you put the powder on is soft, a leather strop for example. Sometimes I dip my finger in the powder to polish dout small defects, that works really well for me (3000grit makes a slightly hazy mirror polish on the finger but a very nasty, harsh scratch pattern when I use the stone). Plus the sharper grit will likely leave deeper and more V shaped gouges than the rounded natural sediment, also making the finish harsher. Everything has it's specific use case, always depends what you need.
Also think I read sharpening stone yesterday?
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Post by larason2 on May 4, 2024 23:33:09 GMT
Yeah, exactly. I've yet to play around with much diamond tooling. I have a 150 grit atoma that I use for lapping unfinished stones to get them into the right shape (which is now very worn!), but for lapping stones when I'm working I always use the traditional Japanese lapping stones. Still it's a great stone and I'm glad I have it, but it feels too coarse to use on steel! I know many use it for that though. I can see they are be useful for some applications, but you're right, the best tool for the job.
Yes, I realize about the sharpening stone! For katana though, and in Japanese culture, sharpen and polish are considered the same thing, and the polish is an essential part of sharpening. I'll use the Shaptons to reprofile a katana's edge, but to blend the edge back into the sashikomi finish, I'll use natural stones (in the past I used the synthetic Namikawa stones), so its somewhat relevant. You're right the Shaptons are probably made for modern stainless knives, and they do work well for sharpening those. Stainless doesn't hold an edge well though. I don't think anything does a good job polishing stainless. The best you can do is a coarse textured polish, (or mirror!) and if you're going textured no matter what it looks blotchy.
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Post by mrstabby on May 5, 2024 7:12:43 GMT
Yeah, exactly. I've yet to play around with much diamond tooling. I have a 150 grit atoma that I use for lapping unfinished stones to get them into the right shape (which is now very worn!), but for lapping stones when I'm working I always use the traditional Japanese lapping stones. Still it's a great stone and I'm glad I have it, but it feels too coarse to use on steel! I know many use it for that though. I can see they are be useful for some applications, but you're right, the best tool for the job. Yes, I realize about the sharpening stone! For katana though, and in Japanese culture, sharpen and polish are considered the same thing, and the polish is an essential part of sharpening. I'll use the Shaptons to reprofile a katana's edge, but to blend the edge back into the sashikomi finish, I'll use natural stones (in the past I used the synthetic Namikawa stones), so its somewhat relevant. You're right the Shaptons are probably made for modern stainless knives, and they do work well for sharpening those. Stainless doesn't hold an edge well though. I don't think anything does a good job polishing stainless. The best you can do is a coarse textured polish, (or mirror!) and if you're going textured no matter what it looks blotchy. I have stones from 240 to 3000 and plates from 80 to 2000, the 80,120 and 180 work well on wood, but on steel? I would never. I had bought diamond stopping sprrays, liked them very much and bought a ton of powdered diamond (it's widely available from 10µm which is around 1000grit up to 0,25µm ~50000grit, around 10€ for 25g and that will last me a while, you need a few milligram t saturate a strop) I now use it to polish everything. ..."Stainless doesn't hold an edge well though."
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I am not sure I agree with that. Any modern stainless with more carbon than ~0,7% will outlast any carbon steel in cutting distance - not even speaking of things like m390 or S90V. Unfortunately also means it gets a lot harder to sharpen - reprofiling S90V is a real chore, and anything but diamond gets eaten by the steel (although the Shapton are said to be able to sharpen S90V, I haven't tried, the glass are made for that). You can definately get a non perfect mirror polish with the 2,5µm diamond powder already, I don't really see much of a difference in finish between stainless and carbon on the 2,5µ, just takes more time on stainless. I am a lazy bastard and have never gone beyond that because "If it works, don't mess with it". Haven't really hit hair whittling sharp yet
That's AUS-8, the scratches are from a 1000grit belt, the polished section is 2,5µm diamond strop (maybe 50x magnification. And I wondered why it won't get sharp, probably because I don't even hit the whole edge with the strop - has a stupid high edge angle which I am not accustomed to, like 30°/Side because it's not a knife but a boot dagger
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Post by larason2 on May 6, 2024 23:32:58 GMT
Haha, I should have known better than to say that! True, some stainless hold an edge very well, but I find the stainless knives I have at home don't hold an edge as well as my Japanese carbon steel knives. But there will always be a stainless that will hold an edge better than carbon steel, you just need to choose the right one! I've not played around with a lot of stainless knives, the two-man Henckels I have being the fanciest I've ever gone. I have a lot of respect for good stainless, I just don't like buying steels that I struggle to get a good polish on!
I have a Japanese synth made for polishing that is 180 grit, and that is the harshest stone I will hazard on steel. If I have to remodel a steel tool a lot, I'll use a 120 grit shapton, but I won't touch any steel blades with it anymore. It doesn't really slurry very much at all, it burnishes easily, and its a lot of work to get a nice polish out of the steel after that.
I haven't had the chance to try much of the diamond powders yet, but I think I will some day, and get a proper strop. There's just so much to play with that I have already, but I recognize they have useful properties. I'd also like to try them when polishing soft metals to see what kind of polish they give. Currently I use charcoal powder or pumice powder for matte, silicon carbide for glossy. They each have their pros and cons, it would be nice to have another option, whether matte or glossy. Plus, I have a reproduction bronze age mirror that I've been struggling to polish with charcoal powder and charcoal. They say that's how they did it back then, but if they did, I don't know how! At some point, just buy the diamond polishing paste, I say.
I'm sure 2,5 um is plenty sharp, I've just never been a stropping guy. Nothing against it though, just haven't had the time to get some of the tools and play around with it. 30 degrees is a pretty broad angle. For knife polishers they talk about the "relief" sometimes, which is basically what lets the edge penetrate into materials to be cut more. They say the more obtuse the angle, the more relief you have to give the blade if you want it to cut well, since you need penetration to get a good cut sometimes. Japanese knives and swords like I play around with generally have pretty acute angles though, so I don't usually have to worry about this too much.
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Post by mrstabby on May 7, 2024 9:40:29 GMT
Most stainless kitchen knives are pretty garbage steel, or at least very entry level and soft. Unless you go for VG10 the 65+HRC japanese knives will win out over the 55HRC stainless (at the same hardness, likely the stanless would win). For western kitchen knives it was decided long ago, that you can't trust the rabble not to put their knives in the dishwasher or let them marinade in the sink, so these steels are primarily selected for corrosion resistance, then toughness and lastly edge retention.
I have never gone below 240 in steel to be honest, it just takes me too long to get the scratches out, but I believe the grit geometry has a lot to do with the finish. The diamonds are not as sharp, you don't have as much influence over the shape when they grow. The diamond grit looks rather dull compared to even normal aluminium oxide abrasives (not even speaking of cubitron and the like that are as sharp as can be). I think they are somewhere between rounded grit of naturals and the more agressive modern stones. EDIT: But the diamond stones still leave a rougher finish than the Korumaku because there is no slurry, unless you use oil, then it's gonna be closer. The loose diamond particles being mobile do good work polishing in my opinion though.
I had never used a strop, exactly because I thought it was too much for me and didn't have the equipment, so I bought a very cheap strop and some compound. In the end I found it's easier than using a stone to get things really sharp and polished. Of course you also add a small convex at the edge, which I also found I like very much. In the beginning not buying an expensive strop is a very good idea, I cut mine up well in the beginning, but I would always buy the diamond compounds again. If you buy, either buy the powder or a spray, the diamond pastes are all oil-based and smell horrible. That smell also infests any object that gets polished. Even the cheaper diamond stuff still will have less size variation in grit than natural abrasives. The materials you mentioned though have something diamond doesn't: They will get finer, the longer you use them. I have read chromium-oxide metal polishes/stropping compounds do this as well, so you can start with a coarser powder that get's finer while you polish(although the diamond stones have a break-in period where theyget less coarse, but it's a one use deal) - you could look at those but personally I dislike chromium stuff because it isn't as medically harmless as diamond or charcoal and pummice, but they are often bundled with cheap strops. I had honestly never achieved a nice mirror finish before I got the diamond compounds except with power tools (more because I am lazy probably....). I had never good nadural stones, so miles may vary. I found a knife I had sharpened as a teenager a few months ago - I have definately come a long way. Looked like a drunk guy with an angle grinder had sharpened it, it hurt.... Do I have to say it though? I don't get a kickback from the industrial diamond lobby
I think the "relief" thing depends on the material, if you have something that tries to pinch the blade when you cut (like batoning wood), but most of the time a straight, low angled V cuts better than a shallower angle or a convex. I just like convex edges because they are more stable on hard targets. I use my Mora on hard wood, and the scandy folded over the first few times I used it, now it's slightly convexed the last 0,25mm or so from stropping and holds up much better.
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Post by mrstabby on May 8, 2024 11:18:30 GMT
Haha, I should have known better than to say that! True, some stainless hold an edge very well, but I find the stainless knives I have at home don't hold an edge as well as my Japanese carbon steel knives. But there will always be a stainless that will hold an edge better than carbon steel, you just need to choose the right one! I've not played around with a lot of stainless knives, the two-man Henckels I have being the fanciest I've ever gone. I have a lot of respect for good stainless, I just don't like buying steels that I struggle to get a good polish on! I have a Japanese synth made for polishing that is 180 grit, and that is the harshest stone I will hazard on steel. If I have to remodel a steel tool a lot, I'll use a 120 grit shapton, but I won't touch any steel blades with it anymore. It doesn't really slurry very much at all, it burnishes easily, and its a lot of work to get a nice polish out of the steel after that. I haven't had the chance to try much of the diamond powders yet, but I think I will some day, and get a proper strop. There's just so much to play with that I have already, but I recognize they have useful properties. I'd also like to try them when polishing soft metals to see what kind of polish they give. Currently I use charcoal powder or pumice powder for matte, silicon carbide for glossy. They each have their pros and cons, it would be nice to have another option, whether matte or glossy. Plus, I have a reproduction bronze age mirror that I've been struggling to polish with charcoal powder and charcoal. They say that's how they did it back then, but if they did, I don't know how! At some point, just buy the diamond polishing paste, I say. I'm sure 2,5 um is plenty sharp, I've just never been a stropping guy. Nothing against it though, just haven't had the time to get some of the tools and play around with it. 30 degrees is a pretty broad angle. For knife polishers they talk about the "relief" sometimes, which is basically what lets the edge penetrate into materials to be cut more. They say the more obtuse the angle, the more relief you have to give the blade if you want it to cut well, since you need penetration to get a good cut sometimes. Japanese knives and swords like I play around with generally have pretty acute angles though, so I don't usually have to worry about this too much. I am just wondering what grit range leaves a mirror polish for natural stones. For example I have seen 50k grit etc, do you need to go that far? The diamonds seem to already leave a pretty good mirror at around 2,5µ/8k if it's loose powder, beyond 8k it does not feel like there is much change in finish. That is only powders though, the finest diamond stone I have is 3k and it still leaves a really scratchy finish - although in some situations the scratch pattern can act like a diffraction grating leaving very cool play of colours in the light, that's always been an accident and never worked when I wanted it to though. So what would you say is the point of deminishing returns for natural stones?
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