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Which cuts faster, and which leaves smoother finish?
- Thread starter chempe
- Start date
In my opinion, metallic bonded cuts faster, but resin bonded leaves a smoother finish.
Metallic bonded stones are similar to plated in terms of feel and finish. Resin bonded are more akin to ceramics. My personal preference is resin bonded for the best combination of speed and finish quality.
Metallic bonded stones are similar to plated in terms of feel and finish. Resin bonded are more akin to ceramics. My personal preference is resin bonded for the best combination of speed and finish quality.
Regardless of its material?
Sorry, I'm not sure what "its" is referring to here.
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The difference between the two is chiefly a matter of grit protrusion. At equal abrasive size and type/grade, more grit protrusion = more aggressive cut but rougher finish produced while less grit protrusion = less aggressive cut but finer finish produced. Think of it like setting the depth of a planer blade.
Regardless the material of the abrasive? You mentioned only the bonding but the question was about the bonding and the material. CBN/metal vs diamond/resin. I wanted to know that how the resin bonding modifies the almost twice as hard diamond compared to the metal bonded CBN.
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So in this the metal bonded CBN should do a more agressive cut doesn't matter if CBN is "softer" than diamond?
Blue Sky
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If the grit size is the same, why would one protrude more than the other? Assuming equal flatness.
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Bond type and surface treatment.
CBN being softer does mean that compared to the same average grain size it will cut less aggressively IF the shape of the grains is comparable. However, CBN and diamond also differ in grain shape and because hardness and cutting aggression, ceteris paribus, depends on the difference in hardness between the abrasive and substrate, it doesn't make as big of a difference in this case as grain shape and grit protrusion because the difference between the abrasive and substrate hardness in this case is always going to be so massive.
I don't think the hardness difference between diamond and CBN is material for knife sharpening as they're both much harder than any blade steel or the carbides in steel. The only time it matters is for high-speed, high-temperature grinding, where CBN is preferred because diamond reacts with iron at high temperatures, which causes the diamond to break down rapidly.
It's more that the heat destroys the diamond, no matter what is in contact with it, diamonds don't like heat.
The other difference here is in bond hardness. The softer the bond the better the finish the stone will leave, right up to not cutting at all.
I'd like to buy a #120 metallic bonded diamond stone reprofiling the edge angle fast. Before stropping I'd buy a #4000 resin bonded CBN.
Between these two grit sized stones is it a good idea to buy a #600 metallic bonded CBN, and a #1500 resin diamond stone, or really doesn't matter too much the bond and the material.
Between these two grit sized stones is it a good idea to buy a #600 metallic bonded CBN, and a #1500 resin diamond stone, or really doesn't matter too much the bond and the material.
With a hard re-profile, I'll start with a 120 grit CBN metallic followed by resin bonded in 150, 240, and 400 grit.
So read most of the thread, sounds like you're just looking for a fast cutting starting progression, then a polished end result? If that's the case, no need to get so hung up on the bond type. I haven't tried metal bonded personally so I'll defer to what others say about it, which is to say, it doesn't polish as well as resin bonded. I do have lots of experience with resin bonded however and it definitely polishes well, some resin bonded are better than others though in terms of polishing. If you want fast cutting, I don't know that you need to spend the big bucks on metal bonded unless you really sharpen a ton and want it to last a very long time. A cheap diamond plate can do that job just as well if not better due to the diamonds sitting on top of the plates, so they'll be able to cut deeper. I think of diamond plates as like a gravel road and resin or metal bonded would be like asphalt and concrete respectively. One is rougher to drive on than the other two, and of the latter two one definitely lasts longer than the other.
Anyway, your grit progression after the reprofiling stone of 600/1500/4000 doesn't sound bad. Could maybe sub the 600 for a 400 for a bit more speed though imo. A lot of stone sets you can buy are something like 325-400/1000-1200/5000-6000 so your suggestion would still work fine imo. I generally don't go below a 300-400 personally for reprofiling. Something in the 120-140 range I've only used for extremely damaged edges since using abrasives that large can stress the edge a bit more than necessary and lead to chipping with some steels in my experience.
That's a good progression, but just so everyone knows, resin bonded stones from Venev use the FEPA grit rating system. The Japanese whetstone equivalents to Venev's 150, 240, and 400 are roughly 150, 500, and 1000.
Good to know that.
Yes, exactly what I'd like to do.
As I read metal bonded doesn't wear out as fast as resin, and cuts faster. That's why I'd choose for the first stone but just when I reprofiling the edge so the first time I use the knife.
CBN maybe a better choice because diamond is more brittle.
777 Edge
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When doing hand sharpening, don't be too concerned about the performance of CBN vs Diamond as the abrasive, both will work equally well. You will never reach the speed & friction needed to achieve the superior thermal performance of CBN during hand sharpening.
The method of bonding does make a big difference though, as mentioned above in this thread.
Plated Diamond / CBN is most aggressive, followed by metallic bond and then resin bonded. Do your hard work & reprofiling with cheap diamond plated stones, and your finishing with your preference of either metallic bonded or resin bonded. Resin bonded will leave a finer end result, which isn't necessarily always what you may desire (depending on the purpose of the knife) but just something to note.
I belived that the toothy edge is better sometimes, for example its better to use on tomato. But I read on scienceofsharp that toothy edge is a myth. The author shows some images of an electron microscope about this. All edges are toothy.
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I think the scienceofsharp conclusion that "toothy is a myth" more of a semantics issue. All edges have teeth, but the question is the scale of them. It's more like a sliding scale of TPI like on a saw blade. A polished edge is like the equivalent of a hacksaw blade TPI whereas a coarse, aggressive slicing edge is more like a large-toothed pruning saw or crosscut for green wood.