Knife Sharpening - First Impression Juuma Cobalt Blue Stones
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- čas přidán 1. 05. 2024
- Steel type used Bd1n
Stones used
Juuma Cobalt Blue 800 and 1200 grits
Dlt xl leather strop with white compound
www.fine-tools.com/juuma-ston...
I didn't get into many details about these stones, as this was a first impression. I need to use them more, to get a feel, for how they work. All I could really get, from this quick session, was summarized, at the end. They are hard, aggression, swarf development, scratch patterns look similar, and they load easily. They require soaking, it seems. I do not know what an optimal soaking time is, yet.
These will see more use going forward, and hopefully, I will give a better description of them, next go round. - Jak na to + styl
Juuma Cobalt Blue are just rebranded Aoi stones made by Miyagoshi. Some JKI Gesshin and Imanishi stones are also manufactured by Miyagoshi.
Manufacturer and vendors states that those stones are vitrified and porous. -> So soaking is necessary.
There is little information and reviews to be found. Your video is very appreciated. Thanks for your inicial impresion and thoughs.
Can you compare speed, hardnees and feel with other stones you have?
You are correct. They make the imanishi 220 pink brick, the imanishi latte 400, and the Gesshin 500. The original Aoi stone is the Juuma 1200. And that basically is the best juuma stone. The 800 and the 2000 is more of a marketing ploy. The Juuma stones require a good 45 min soaking and high initial pressure until the release a bit of slurry. Cutting performance is similar to shapton pro stones, but the juumas have a bit more tactile feedback. The stones shine with steels such as 440c, vg10, super blue, D2 etc
Thanks for all that information. I will try to mention it next time i record these stones.
Enjoyed the video
Thanks for checking it out. I forgot i had scheduled this one. Was still debating if i was even going to make it public, since I didn’t go into much detail, about the stones 😂
Cheers 👍
🤙
Looks good mate hope all is well 🙂
Thanks bro 👊
Maybe light edge trailing strokes to break burr off? Just a thought
Edge leading is the way to go. Edge trailing, tends to create burrs. Not an ideal move, for removing them. Everyone has they own way of doing things. If it works for you by all means 👍
Nice video Jeff. Been curious about these fine tools stones for a long time but never tried em. you should try a king neo 800. it's sic. it's $35 on amazon japan. comes in a roughly 2+" x 6+" or 8"x3" attached to a base or not. it's one of my all time favorites. its a soaker but not much more than a chosera honestly. cut everything. cuts really nice. leaves a very nice edge.. feels a lot like a chosera, not the 800 though. feels somewhere between the course ones, like the 400 and 600 and creamy 2k and 3k stones. very hard, wears slower than most choseras. doesnt release much grit at all so there is no mess or mud unless you want it and lap it first. and it leaves a really nice hazy finish on stainless cladding for doing wide bevels. honestly one of my favorites at any cost and it's not much. BBB raves about them too.
I’ve been told about that neo stone by many folks. I need to just suck it up and buy one 😁
Is there any more in the neo series or is it a one off?
Thanks man 🙄. For some reason your description made me promptly hop on Amazon and buy one. And one of the restaurant sized Deluxe 1000s 😆
@Jef So I got my King Neo 800. I have to agree it's a wonderful stone. However, I would not call it a hard stone 🤷♂️ The OP of this thread compared it to Choseras in hardness, and while I've only owned the 1k Chosera due to their known cracking issues, I would not put the King in the same hardness class. To me it's medium hardness at best and my stone is fairly friable and absolutely does release grit and slurry from the stone, and I'm not a heavy handed sharpener. IMO opinion it's true friability and not just entire pieces of abrasive letting loose, like a Shapton Pro 320 etc. I'm not saying this as a negative, I just don't agree with a few of his claims. I have only hit it with a diamond plate real quick to verify it was flat and take the very top layer of the stone off, and then conditioned the surface with a nagura. So it's possible the stone hasn't shown its true colors yet. All that being said many of his other opinions I agree with. Cuts just about anything excellently. Has a nice, creamy feel to it while having some aggression simultaneously. Leaves an excellent edge and finish for an 800 as well on the steels I've tested it on, which was S30V (Spyderco's), CPM-M4 and D2. Would make an excellent 1 and done type stone for stainless folders in particular IMO, but also fit nicely into a progression. I'm very impressed with it, it's just not hard in the way I think you prefer. Not so soft you're gonna be snowplowing it but easily gouged by the tip if you're not careful. It does have an excellent feel to it and very responsive tactile and audible feedback. It's very nice in that way. Lets you know exactly what you're doing with the bevel. Definitely a keeper and I see myself using it often for steels often found in high quality folders and some stainless Japanese knives that are regularly taken to 62-64 Rockwell. Has the speed to bring back a dull edge quickly but also leaves an edge that doesn't leave much to be desired. If they made an entire line of them I would buy them but so far the 800 is all I've come across
Wow, thanks for that write up. Exactly the kinda info that makes for a fantastic review. The hardness you describe sounds like many coarse grits available.
Many have that friability you describe, which helps them cut so fast. The constant release of fresh sharp abrasive. I am just going to have to break down and purchase one myself, it seems. Everyone that has used one, has raved about it. Can’t be bad right?
@@Jef i made other comments about it but they never showed up. youtube is weird. you should 100% try it. I know you will like it. imo, and I probably have as many as you do, it's very similar in hardness and friability to the 2k and 3k chosera with a similar wear rate and feel but obviously courser. It's not a course stone but it cuts quite quickly. easily faster than 500 glass, either 1k or 800 chosera.
Love your channel and what you bring to knife sharpening brother. Thanks from New Zealand 🌏🌏🌏😝👊🔪🔪🔪👏👏👏👏😎🤘
Thanks! Appreciate the hell out of the support
What steel is the knife you sharpened ? Love your videos very knowledgeable.
I thought i mentioned it. If not i should have. It is Bd1n. Easy to grind stuf
hey brother can you tell me what kind of tub that is or or sharpening pond your using. Thanks.
www.amazon.com/Rubbermaid-Commercial-FG330900CLR-3-5-gallon-Included/dp/B000VAUFRW/?_encoding=UTF8&pd_rd_w=ilGHb&content-id=amzn1.sym.278a231e-7496-43c2-a864-2367bca2eeb2%3Aamzn1.symc.c32ea383-0406-481f-aa79-ef5129d2367b&pf_rd_p=278a231e-7496-43c2-a864-2367bca2eeb2&pf_rd_r=TWJ5S7BZPAEQ8D63R1VY&pd_rd_wg=6j4nk&pd_rd_r=cbfddf31-c0ab-41d4-bc7b-ade50733461a&ref_=pd_gwm_ci_mcx_mr_hp_m
Jef, how do you dispose of your sharpening stone water, in the sink or something else?
Awesome question! I spoke about this in one of my flattening videos. I usually take it outside and dump it. If it is light in moisture, I’ve even dumped it in my trash can. In this scenario, however, i had very little cloudiness in the water when finished; i just tossed it down the sink. Not the best option, since the sediment can eventually build up, and cause plumbing issues. I’m in an apartment currently, while saving for a house. Not really concerned with it here 😂
Another video from Jef triggering my whetstone addiction 😅 Interesting video though, I've been wondering about these. You said they have a reputation for being fast but they didn't really look very fast to me. You said you lapped them so you shouldn't be dealing with a "crust"? They look and sound hard, maybe it would help with speed a bit if you developed a little bit of a slurry first. I would expect most stones to raise a burr on a narrow bevel of that steel fairly quickly
Yea the second side burred quickly. The first side, was stubborn. Dunno what that was about. I was spouting what little heresy, i had on these, from watching neuman2000? Think that’s his handle. The guy who developed the washboard system. He has shown the 800 in a few video’s, and discussed them. Yes, i lapped both. No crust, but they weren’t conditioned either. I’m sure doing it properly, or even with slurry, (that was suggested by another, as well) would yield faster results.
@@Jef I remember hearing somewhere the 1200 is the most highly thought of Juuma. And honestly I'm not really one of those guys that think slurry will increase speed very much but who am I 😅 Still interested in them because like you, I'm a sucker for hard stones (depending on the knife and steel I've learned, I'll often choose a softer Suehiro lineup for more abrasion resistant steels or steels that have been taken to a high hardness). Just ordered a King Neo 800 that one of the commentors in this video somehow convinced me to buy with one comment 🙄 A hard king ( I'm hoping it feels like a King Deluxe 300 - awesome stone) using green SiC sounds very appealing to me for stubborn steels. King stones are underrated in my opinion. I like the King 300 more than almost all of the other coarse stones I own, it's excellent. Very hard, doesn't load up, cuts fairly aggressively (although I think I would rate the finish/scratch pattern it leaves closer to 500-600, still cuts with the speed of a 300) is essentially splash and go and seems to have no problem with high end steels. Great one for you to try if you haven't
Yes king are over looked often. The deluxe 1200 used to be one of my favs. Then i discovered the Imanishi 1k, and forgot all about it. Still, it is a solid choice. Very predictable cutting speed. Not too slow; not too fast. The king 300 green sic I’ve heard varying opinions on. One from a guy i trust said it was very friable, and released grit too quickly. Never tried it myself but sounded like something i would avoid. Which is why i never grabbed one. I believe I’ve seen virtuvice using it in some of his old videos too. If it was the same stone, I’d draw that same conclusion. Too friable. Perhaps the formulation has changed or the stones i am thinking of were a different grit 🤷♂️
@Jef That sounds like a different stone to me. The current King Deluxe 300 that I have is a light blue color, I'm not sure if it's aluminum oxide or SiC, but it cuts all the steels I deal with regularly just fine. And it's the opposite of your typical friable stone. It releases VERY little abrasive, just enough to not load up or glaze over. And it's very hard, like way harder than the King 1000 or 1200 ( have both of them also). FAR less friable than the low grit Shapton Pro stones like the 320. Less friable than the 1k Shapton Pro even IMO, possibly equally so. I wouldn't recommend you a soft, friable stone 😉 I honestly think that stone would be right in your wheelhouse
Plan on grabbing the neo stone. May as well grab the deluxe 300 while i am at it 🤓
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