Where are the boron carbide (B4C) stones?

M

Mr.Wizard

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Feb 28, 2015
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In recent years people have started using/making diamond and CBN stones (not plates) for sharpening. These are expensive raw materials, and seem to have leapfrogged one notable option: boron carbide. Boron carbide is harder than silicon carbide, but much less expensive than diamond. It is often used in grinding wheel dressing sticks. Why aren't boron carbide whetstones more common?
 
With a name like Mr. Wizard, shouldn't you be telling us? ;)

Seriously though, I'm sure some of the subject matter experts will be along shortly.
 
Seems like most of the boron carbide stones I've seen are produced by the Chinese, most of them exist in the coarse to medium grit range.

https://www.aliexpress.com/item/LEE...e0-4ae1-b698-8ef6f1a4e50e&transAbTest=ae803_4

@Gritomatic Sells some boron carbide stones for the Edge Pro / Hapstone / TSprof, perhaps they can provide some insight into the market.

https://www.gritomatic.com/collections/edge-pro-stones/products/boron-carbide-stone-edge-pro

D Diemaker Has made boron carbide stones according to a post made in the Diamond Matrix thread, perhaps he can share his experience with it.
 
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I like diamond for the high end steel but admit to no experience with boron carbide hones. (Shapton Glass for the next step down from the higher vanadium carbide steels.)

For the lower end / softer steel my wife likes to use in the kitchen...Tramontina, Boker, Victorinox...I prefer to use a 1000 grit King water stone. They seem to respond very well and it's a joy to sharpen with.
 
Mr.Wizard said:
Blues Blues Touché.

Ocelot85 Ocelot85 Are those Chinese stones really B4C? I am skeptical. I wasn't aware of the Gritomatic product however. Thank you.

I found the post you referenced; it's quite helpful.

https://www.bladeforums.com/threads...d-diamond-stones.1590536/page-2#post-18412617
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I can't make any claims to the authenticity of the Leeped B4C stones I don't have any personal experience with them, I've just seen them around and besides the other examples I quoted I haven't really seen B4C whetstones often. They're not too expensive so perhaps I'll roll the dice on one and see what I get, who knows maybe it'll be a brick spray painted black.

I would like to try out B4C stones on carbon steels and stainless steels with a low Vanadium carbide content. I would like a longer lasting low wear option compared to the stock Edge Pro aluminum oxide stones, and something that is less aggressive than the Diamond Matrix stones on softer steels.
 
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Ocelot85 said:
I would like a longer lasting low wear option compared to the stock Edge Pro aluminum oxide stones, and something that is less aggressive than the Diamond Matrix stones on softer steels.
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That sounds like a good reason to try Shapton Glass or even something like a Norton Fine India.
 
Blues said:
That sounds like a good reason to try Shapton Glass or even something like a Norton Fine India.
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I've been looking at the Boride Engineered Abrasives T2 stones in the 6MM thickness for an aluminum oxide option if I can't get a B4C option in multiple grits.

I would follow either option with either polishing tapes or a strop loaded with compound.
 
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What would be the reason for cbn vs the many many choices in diamonds? Now for straight razors some feel that cbn creates a better feeling edge. Although I dont use any paste for my razors. Just curious what the reasoning is. If its to have the latest and greatest thats fine also. But is there a useful reason to buy these if you have atomas and dmts?
 
Ocelot85 Ocelot85 Which Edge Pro stones do you find to wear too quickly?

B Bill3152 If your reply is to me, not Cubic Boron Nitride but boron carbide. CBN is much more expensive. Boron carbide should theoretically be a step up from alumina and SiC without great expense.
 
Mr.Wizard said:
Ocelot85 Ocelot85 Which Edge Pro stones do you find to wear too quickly?

B Bill3152 If your reply is to me, not Cubic Boron Nitride but boron carbide. CBN is much more expensive. Boron carbide should theoretically be a step up from alumina and SiC without great expense.
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Thanks! What I'm curious about is if someone has atomas and dmts would they get anything out of these stones?
 
I got some boron carbide in 80 and 125 micron to try out. I found I like it on a friends Cusinart knives, but nothing much harder. I have tried them on CPM 4v @ 64Rc and found they didn't even scratch it much. Keep in mind this is with a resin bond, which is a pretty low aggression bond, so this is a big factor. Since the Matrix stones work with fairly soft steels, Chicago kitchen knives is the softest I have, I really haven't put much effort into finding something else. If your knives are too soft for Matrix stones to at least work, then plain alox works great.

I too have been curious why there are no boron carbide stones like alox and sic. Maybe it's more of an expensive version of sic than a cheap version of diamond or cbn? On paper it looks impressive.
 
Mr.Wizard said:
Ocelot85 Ocelot85 Which Edge Pro stones do you find to wear too quickly?

B Bill3152 If your reply is to me, not Cubic Boron Nitride but boron carbide. CBN is much more expensive. Boron carbide should theoretically be a step up from alumina and SiC without great expense.
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The standard Edge Pro stones are fine as far as aluminum oxide stones go, but I would still like a thicker and slower wearing stone if possible that gives a good finish on softer carbon and stainless steels. That's why I would be interested in B4C stones, I may try Gritomatic's offering but I was hoping to have more choices in grit range.
 
Diemaker said:
I got some boron carbide in 80 and 125 micron to try out. I found I like it on a friends Cusinart knives, but nothing much harder. I have tried them on CPM 4v @ 64Rc and found they didn't even scratch it much. Keep in mind this is with a resin bond, which is a pretty low aggression bond, so this is a big factor. Since the Matrix stones work with fairly soft steels, Chicago kitchen knives is the softest I have, I really haven't put much effort into finding something else. If your knives are too soft for Matrix stones to at least work, then plain alox works great.

I too have been curious why there are no boron carbide stones like alox and sic. Maybe it's more of an expensive version of sic than a cheap version of diamond or cbn? On paper it looks impressive.
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All of the B4C stones I've seen or heard of besides yours have been sintered, a lot of times it seems that they combine them with a sintered corundum / synthetic ruby that is a finer grade.
 
Don't expect a boron carbide stone to be magic, the bond/binder is what determines most of the wear rate. For softer carbon and stainless steels it probably won't be any better than alox.
 
Diemaker said:
Don't expect a boron carbide stone to be magic, the bond/binder is what determines most of the wear rate. For softer carbon and stainless steels it probably won't be any better than alox.
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I don't expect magic I never said that, but it doesn't hurt to experiment and find out how they'll work. I'm also looking at other longer wearing aluminum oxide stones such as the Boride Engineered Abrasives T2 series stones which have a different slower wearing binder. I was going to experiment between these options, I wasn't expecting anything miraculous.

Also I bought the entire line of Diamond Matrix stones, they work great on high hardness high wear steels. I've personally never really liked the edge diamond plates put on softer carbon and stainless steels though, I've always went back to aluminum oxide or natural stones like Arkansas stones for them.

Bottom line is that nothing in sharpening is perfect, there is no perfect system. They're all compromises in some form, and I like different abrasives for different reasons.
 
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B Bill3152 Not everyone likes the feel of diamond plates, and they get less and less aggressive with use. A stone that can be resurfaced to cut like new is appealing.

Ocelot85 Ocelot85 It sounds like a 1/4" thick T2 stone should suit you well, as long as you're OK with it not holding lubricant as well as the AS-9 series.

D Diemaker thanks for your professional insight. I expect that diamond is better nearly universally, but also expensive. What might the relative cost of BC stones be?

If I read your other thread correctly it sounds like you have several resins to choose from; which did you use for the BC stone prototypes?
 
Ocelot85- I have several questions but don't want to go off this posts topic. Have you tried the Matrix stones on your softer steels? The resin bond is totally different than any of the other bonds. I understand having more toys in your toybox is fun, I have a bunch plus I get to play with whatever EP has in their toybox too.

Mr.Wizard- Since the material cost is such a small part of the retail price the difference will probably be driven by volume.
 
Diemaker said:
Ocelot85- I have several questions but don't want to go off this posts topic. Have you tried the Matrix stones on your softer steels? The resin bond is totally different than any of the other bonds. I understand having more toys in your toybox is fun, I have a bunch plus I get to play with whatever EP has in their toybox too.

Mr.Wizard- Since the material cost is such a small part of the retail price the difference will probably be driven by volume.
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Not to go too far off-topic but yes I have, I've sharpened some AUS-6 with them. They left a large burr and I had to be very careful with my pressure otherwise I would get some errant deep scratches. I started with the 80 grit because I had to put a entirely new bevel on the knife and progressed up to 650, I then switched to the 600 grit aluminum oxide stone and felt that the finish was superior with the aluminum oxide over the diamond for this soft of steel. It left less of a burr and fewer deep scratches in my opinion.

I don't say that to take anything away from the Diamond Matrix stones, I love them on my high end knives and I've put mirror polished edges on those knives with your stones combined with Jende Industries diamond lapping films and emulsions. I think they're the best option for hand sharpening hard wear resistant steels that I've found so far.

I'll try them out on some 1095 carbon steel tonight if I get time and reply in the appropriate thread.
 
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