Spyderco soon releasing a CBN bench stone

maximus83 said:
^Yes. See the article I linked earlier on benefits of CBN. Again, its benefits for grinding applications are mainly:
  • Withstands heat, especially during high-speed applications
  • Does not cause grit that can dull bits
  • Stays sharp and cool because it does not react with steel
Also BTW, note this interesting blurb at the end of the article, kinda' caught my attention with regard to future applications of cbn:


Now back to our world: I think for manual sharpening application, the first and third bullets above are mostly irrelevant. However the second point could be germane to DM's question, if Spyderco manufactures the CBN right and its well embedded on the plate, in theory during the process of sharpening it should not shed as much grit onto the steel being sharpened. Obviously the proof will be in the pudding there, it's never just a theoretical question of how CBN "should" do X or Y differently from diamonds, it's always in an actual implementation in a real stone that somebody makes. Because as we've all seen, you can't just generalize about how 'diamonds' work in all cases, you always have to look at a particular diamond plate: DMT, Atoma, Ultrasharp, somebody else, they have similarities, but all can work quite differently, wear out faster, produce a different finish, etc.
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Sounds like I'd have to get a Cbn plate and compare. Am not sold on its superiority to diamond at hand speed or slow mechanical.

It isn't used much in lapidary work, but again that might be due to mineral shape or cost as opposed to durability.
 
HeavyHanded said:
Sounds like I'd have to get a Cbn plate and compare. Am not sold on its superiority to diamond at hand speed or slow mechanical.

It isn't used much in lapidary work, but again that might be due to mineral shape or cost as opposed to durability.
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Agree HH. As with some past plates you did an eval on, would love to have you get a hand on Spyderco's CBN, compare to your DMT's, and give a real-world eval on how you think it stacks up as a 'primary' or 'one-plate' solution for us home sharpening amateurs.
 
CBN is not used much in industry except for that one application. Diamond is better in every way otherwise. One example - I have a CBN grinding wheel on my drill grinder. It can grind hardened steel just fine. Try grinding a tungsten carbide drill bit and the wheel rubs more than cuts, creating a lot of heat. Diamond is still the king so far. It will be interesting to see if they ever accomplish anything with that "ultrahard" CBN method. Just because something can be done in the lab doesn't mean it can be useful in the real world. Often the cost is prohibitive or there is no good method to scale up a lab result to real life on a production scale.

I would certainly try out a CBN bench sharpening hone, but I wouldn't expect it to be better than diamond. I would be very interested to see a wear comparison in a controlled setting. It would be interesting to see which cuts more freely when new for the same grit and how that speed falls off during use over time. I made a testing fixture once for measuring the cutting speed of various sharpening stones, it was neat to see the different cutting speeds quantified.
 
  • Withstands heat, especially during high-speed applications - Which only matters when plating for our needs. CBN is much easier to adhere to with metal alloys as well.
  • Does not cause grit that can dull bits - ????? No idea what this means.
  • Stays sharp and cool because it does not react with steel - How many strokes a second can you attain sharpening your knife? If it's under 20 then this is irrelevant. An interesting thing about diamond is it is over 3 times better at thermal conductivity than pure copper.
One thing to think of is diamond is used to grind sintered carbide, think end mills and lathe inserts, not CBN. If the heat can be controlled then diamond is better since it is quite a bit harder. I think there is more variation in quality with diamond vs CBN though since there is a lot more made and it is about 1/10th the price so you can't say all diamonds are the same, same with metal bonds. You can get your diamond powder tailored to better edge retention or better toughness, kind of like steel with the same compromises.

I used to make my own rotating tool bodies, drills, routers, face mills, and radius cutters, then have them coated with diamond powder using a nickel and reactive metals alloy in a high vacuum furnace to machine different stones, ceramics, and man-made quartz surfaces. If I did 3"x8" plates it would probably be around $400 each in batches of 5, not cheap but very high quality. I did not worry about diamonds fracturing off or pulling out unless something bad happened with the tool, it was amazing what they could endure and keep cutting. This was with between a 25% to 50% bond line, that is the bond only held onto that much of the diamond crystals, it didn't cover them. I am willing to bet that how long a plated stone lasts has way more to do with how well it was made vs diamond or CBN.

Because of the bullets I couldn't add anything to the top of this post. After writing it I wasn't sure it was worth posting but am doing so if only to support what eKretz is saying.
 
Diemaker said:
I am willing to bet that how long a plated stone lasts has way more to do with how well it was made vs diamond or CBN.
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Yes, that is exactly my take on the issue of durability. And similarly, I'd bet that the resulting edge and finish that one can get from a particular diamond or cbn stone used for freehand or manual sharpening, will be more a function of how the stone was made, than whether it embeds diamonds or cbn.

That said, I am intrigued that Spyderco, for all their recent sharpening stone options that are capable of sharpening their own super steel knives (the doublestuff 2, the more recent cbn Sharpmaker rods, and now the bench stone), have chosen CBN. That could be for multiple reasons (they found a good deal on manufacturing cost, bringing something 'unique' to market where there are already many diamond plate offerings, etc.), but I have to think they ALSO chose CBN because they think they can get good sharpening results with it. That, and my hands-on experience with their other CBN, is what's really driving my interest more than just the novelty of the CBN itself.
 
I am sure marketing plays a large factor and since your only cutting steel with it then CBN isn't much of a drawback, remember it isn't as hard as diamond. It may hold up better if too much pressure is used when sharpening but a lot of that depends on the diamonds used. Still, it is an interesting entry to the field. I would love to look at the bond to abrasive interface with my microscope, both new and after some use. That is what tells a lot of the story.

As for finding a good deal, yeah, they did, in China.
 
^Well, $91 to be exact. That's the pre-order price I'm seeing for retailers that support this forum. But yeah I agree, pricey and not for the faint of wallet.

But to give that a little context: a well made dual-grit, dual-sided plate of similar size like the DMT duosharp actually costs in the same ballpark, though you can find for $20 cheaper to actually higher as in that link.
 
CBN costs more than Diamond.

The double side DMTs are not continuous plates they have holes in them so you're not getting as much diamond.
Even if getting a DMT don't waste money on the non continuous plate. The holes only seem to increase DMTs profit margin by reducing cost.



maximus83 said:
^Well, $91 to be exact. That's the pre-order price I'm seeing for retailers that support this forum. But yeah I agree, pricey and not for the faint of wallet.

But to give that a little context: a well made dual-grit, dual-sided plate of similar size like the DMT duosharp actually costs in the same ballpark, though you can find for $20 cheaper to actually higher as in that link.
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Agree that in general if you shop around, CBN is often higher than the most comparable diamond option in most sharpening applications, whether you're talking Tormek grinding wheels, field sharpeners, stropping compound or bench stones. But my point is really that for anyone prepared to get a quality diamond plate by a recognized brand say Atoma, DMT, etc., this CBN is in the same ballpark and is not an unreasonable price. Sure ideally I'd rather have a $30 diamond plate, but I don't know about you, but I'm not as happy with the finish that my cheapo diamond plates produce versus say my coarse DMT. So for me, when it comes to sharpening my high carbide steels, I'm willing to spring for a good name-brand diamond (or now, CBN) sharpener. And given what comparable sharpeners/features cost, the Spydie doesn't seem crazily out of line. Take a specific DMT offering that I think is the best direct alternative to this Spydie CBN, the Duosharp Coarse/Fine 8" stone. It costs $77 at the big river place, which last time I looked around, that's a pretty competitive price on that dual-grit DMT plate. A $91 spydie CBN (which let's be real, will probably come down in price after it's been on the market a while, like the DMT) is $14 more for its pre-order price. It just isn't that big of a different to be concerned about, if I was interested in this plate for other reasons, it's just not that much more than a comparable quality diamond plate.
 
maximus83 said:
Agree that in general if you shop around, CBN is often higher than the most comparable diamond option in most sharpening applications, whether you're talking Tormek grinding wheels, field sharpeners, stropping compound or bench stones. But my point is really that for anyone prepared to get a quality diamond plate by a recognized brand say Atoma, DMT, etc., this CBN is in the same ballpark and is not an unreasonable price. Sure ideally I'd rather have a $30 diamond plate, but I don't know about you, but I'm not as happy with the finish that my cheapo diamond plates produce versus say my coarse DMT. So for me, when it comes to sharpening my high carbide steels, I'm willing to spring for a good name-brand diamond (or now, CBN) sharpener. And given what comparable sharpeners/features cost, the Spydie doesn't seem crazily out of line. Take a specific DMT offering that I think is the best direct alternative to this Spydie CBN, the Duosharp Coarse/Fine 8" stone. It costs $77 at the big river place, which last time I looked around, that's a pretty competitive price on that dual-grit DMT plate. A $91 spydie CBN (which let's be real, will probably come down in price after it's been on the market a while, like the DMT) is $14 more for its pre-order price. It just isn't that big of a different to be concerned about, if I was interested in this plate for other reasons, it's just not that much more than a comparable quality diamond plate.
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The difference for me is that DMT is US made, Atoma is Japanese. Paying the same rate for Chinese made doesn't make financial sense, esp when Cbn plates already exist. If it were made in US or other country with higher cost, I'd be more inclined, or if it gets rave reviews...

Personally I think DMT plate quality is much higher on the interrupted surface plates than the continuous, easily equals out the dif in materials.
 
HeavyHanded said:
The difference for me is that DMT is US made, Atoma is Japanese. Paying the same rate for Chinese made doesn't make financial sense, esp when Cbn plates already exist. If it were made in US or other country with higher cost, I'd be more inclined, or if it gets rave reviews...

Personally I think DMT plate quality is much higher on the interrupted surface plates than the continuous, easily equals out the dif in materials.
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Yeah I agree about the DMT, I have both continuous and interrupted. Both work, but it seems like all things considered over about a 10-yr period, I've had less issues with the interrupted ones than the continuous ones, sometimes it seems like the interrupted ones were also more flat, but in any case I've preferred working with the interrupted.
 
Diemaker, I'm with you. I won't purchase the Duo- stone because it give 50% less diamond material. A marketing employee's dream scenario. The Dia-"sharp gives you more material for your money. But the grit will sheer off. So, I 'm hoping the manner they attach the cbn grit is better. Plus, I'll wait for the reviews. DM
 
There is one thing I can tell you about both Atoma and the steel backed DMT plates that is very nice. They are very flat, and believe me, I have checked. This is very useful in a scenario where you need to quickly flatten something, for instance. I use mine all the time for that in addition to sharpening. Sure beats setting up the surface grinder or a lapping plate with the mess of loose grit. For purely sharpening purposes it's not that big a deal, but for those of us who also use them in a shop setting, that flatness is a very good thing. I have a grand total of 3 Atoma plates and 10-12 varied sizes and grits of DMT plates. I have checked all of them on a surface plate and not a single one is even .001" out from planar. The Chinese-sourced plates I've checked have been all over the place, and not even consistent within a brand.

And yes, diamond can shear from the plate and the edges of the individual grit particles can become rounded off, making them duller and requiring more force to cut well, but they wear very little in terms of height loss. Some of the plates I checked had years of wear on them, including lapping other hones flat. Still less than .001" out. It would be interesting to check a CBN bench hone with similar use on it, but I don't have one of those.
 
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^Good to hear about the higher quality plates/products, kinda' reinforces what I've seen too, though it sounds like you have a greater sample size.

Related Q to thread, since apparently Spydie is getting this CBN manufactured in China: Does anyone know of quality CBN bench stones (not asking about Edge Pro, or other small stones for guided sharpeners) made in the US or other non-Chinese countries? I suppose given what we've already been agreeing to throughout this thread (that CBN is mostly superior to diamond in certain grinding applications, that CBN today seems to usually cost more than diamond, etc), that there isn't really a big demand for making CBN bench stones.
 

Made this video 2 years ago, might help.

maximus83 said:
^Good to hear about the higher quality plates/products, kinda' reinforces what I've seen too, though it sounds like you have a greater sample size.

Related Q to thread, since apparently Spydie is getting this CBN manufactured in China: Does anyone know of quality CBN bench stones (not asking about Edge Pro, or other small stones for guided sharpeners) made in the US or other non-Chinese countries? I suppose given what we've already been agreeing to throughout this thread (that CBN is mostly superior to diamond in certain grinding applications, that CBN today seems to usually cost more than diamond, etc), that there isn't really a big demand for making CBN bench stones.
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You're hitting at some of the short comings I have noticed on platted/ coated stones. Where as the resin bonded would be more like a Norton India. Very slow wearing and more expensive. Yes, the difference shows up as you sharpen more knives. DM
 
Their are some advantages to plates.

Lower cost is the obvious one.


The more discerning advantage is the deeper cut makes a more aggressive microserration, one can do a simple test on Manilla rope and see that for the same grit size say 400grit JIS, the plate will make a better rope slicer with sawing and drawing the edge across the fibers.

However, it comes at a cost to some edge stability, one can compare the edges of a plate and a bonded stone and drag at 90° across the cutting board and notice the plate edge is easier ruin the apex shape on. Given that the deeper grooves mean less material support at the apex and deep scratches can also act as stress risers.

Being the only person in this thread with first hand experience with DMT, ATOMA and the Spyderco CBN plate I can say that spyderco plate is better constructed than the DMT plate which had disappointed me in the past and served as a catalyst for my deep dive into sharpening stones.

It's not just a film attached to a plate like the DMT but is appears to be electroplated to a plate adhered to thicker plate in the middle.

I see some complaints here about cost, however, a 8x3 DMT continuous plate single grit is around $60.

The Spyderco is 2 grits for under $100 with better construction and the more expensive CBN to try.

So it's not priced out of market, it's actually a better value.

The CBN on a plate is a curiousity for folks to try it doesn't mean it will work like a more exotic bonded stone, or be invincible.

It's still a plate.

It may have features that are different in controlled testing that may be marginal anecdotally but some folks may see the merit.

It makes sence for Spyderco to move towards having some super abrasive sharpening products given that they are the only company giving people production Maxamet steel on folders which is insane and deserves respect.

David Martin said:
You're hitting at some of the short comings I have noticed on platted/ coated stones. Where as the resin bonded would be more like a Norton India. Very slow wearing and more expensive. Yes, the difference shows up as you sharpen more knives. DM
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