Experience with Spyderco's CBN benchstone?

[dull&blunt]

I own a KME but would like to learn how to freehand sharpen on benchstones. My steel list includes 154CM, S30V, Rex 45, M4, 4V, Cru-wear, 15V and more. Not necessarily looking for mirror polished edges, just really sharp. I've done some research on here and other forums, I'm pretty sure I'll need 400 an 800 grit stones to achieve this. I have several freehand strops with Venev compound to follow the progression.

Spyderco's CBN benchstone seems to fit my needs perfectly. And $100 for both grits doesn't seem like a bad price after looking into Atoma and Naniwa stones.

Does anyone here have experience with the CBN stone? I would love to hear your thoughts. Or other stone suggestions that I might look into?

[jmj3esq]

I have never been able to get a straight answer on whether CBN or diamond is best for hard tool steels. I currently work with diamond, but would be willing to change if CBN is king. Ant help?

[wokel]

This is an excerpt I found on the Canadian Woodworking and Home Improvement Webpage:

"The 306CBN is comparable in price to a monocrystalline diamond-coated sharpening stone. It offers much better value than a Waterstone in that it’s harder, more durable, lasts longer, and will never need to be flattened. And you’ll get back to what you enjoy more quickly – working wood."

as well as

"There are several reasons that CBN is worth considering for your next sharpening stone. Most important is that CBN is harder and has greater abrasion, thermal and chemical resistance than either synthetic diamonds (though less so than natural diamonds), silicon carbide, or aluminum oxide. Unlike other bench stones, you can use it dry (without any lubricants). It never requires flattening (though in all fairness neither do diamond stones) and it will sharpen any tool steel, including the S90V produced by Crucible."

I believe that there is not normally a "best" stone for sharpening tool steels, but more of an "it depends on what you want out of it" type of answer. If you want a long-lasting, high-value (but relatively low-cost) stone, I would recommend it.

[bbturbodad]

I have never been able to get a straight answer on whether CBN or diamond is best for hard tool steels. I currently work with diamond, but would be willing to change if CBN is king. Ant help?

They are both hard enough to cut the carbides in any blade steel. CBN tends to have a more uniform structure which results in a more even scratch pattern. This is more noticeable with lower grits as the abrasive particles are larger, as you move to finer grits you're less likely to see the difference unless you are really looking for it. If you're currently using diamonds I would stick with that. If you were starting from scratch or had an old stone that was worn out I'd probably go with CBN.

[vivi]

I'm gonna watch this thread. I've been rocking my cheap HF stones but have planned to buy one of these eventually.

[Hopsbreath]

I'm gonna watch this thread. I've been rocking my cheap HF stones but have planned to buy one of these eventually.

The HF does an adequate coarse job, especially for the price. I do prefer the Spyderco CBN stone for a more refined and consistent edge though. It didn’t take quite as long to break in.

[dull&blunt]

Thank you to everyone who has joined in with your experiences with the stone.

I had heard that CBN stones produce a more uniform scratch pattern. And if I only plan on sharpening to 800 + stropping, I would certainly appreciate the better ascetics of the edge.

Does anyone see any encumbrances with the two grits (400 & 800 + strop)? The most intensive sharpening I see myself doing is either reprofiling an edge or repairing minor damage. And 800 grit + 3 micron strop should provide a very nice working/long lasting edge, no need for anything much higher (again, not worried about getting mirror polished egdes). I guess I'm asking, this stone should be able to provide that for me, correct?

[WilliamMunny]

BBB himself did a review on it and liked it:
https://youtu.be/H37NEs0qUkw

I have both work sharp Diamond and Spyderco CBN rods… I don’t tell a difference.

The best is bonded diamond stones. The diamonds are throughout the stone. With sharpening new diamonds will appear.

[Bemo]

I have bonded diamond, bonded CBN, DMT, and the Spyderco CBN bench stone (among a bunch of others, let's not talk about that). I think the Spyderco CBN is a great deal and you may have found a 1 stone solution for your sharpening needs for a long time.

[olywa]

I liked Spyderco CBN Sharpmaker rods and Gauntlet cat-eye CBN rods so well that I picked up the CBN benchstone as well. I'm no pro, but in my experience it works well for free-hand sharpening as long as I remember to use a light touch. My Diamond Sharpmaker rods were the casualties incurred in the learning of that lesson. I've been much kinder to my CBN surfaces and they've rewarded me for it.

[gumaropa]

Hi dull&blunt,
I use the CBN benchstone to sharpen archery broadheads, especially single beveled ones like the Grizzly broadheads. I use the KME Self Aligning Broadhead Sharpener, and the benchstone offers a large and very flat surface that handles wide cutting surfaces (much better than using sand paper with backing). I tend to lubricate the surface with a drop or two of water to lower on the dust, and once I am done, I rinse to remove the steel particles and air dry it. So far this is the best setup I have found, with very repeatable results sharpening the same head after use. I hope this helps.

[Bolster]

Since I use the Sharpmaker for touchups (only), I'd really appreciate a fine grit CBN or diamond rod.

[Traditional.Sharpening]

I would reserve the plated abrasives exclusively for apexing as I believe stones which generate a slurry are ideal for actually shaping/thinning/restoring the edge bevel to the appropriate shape and thickness prior to setting the apex. The slurry will naturally and strongly resist burr formation, assuming the stone is not very coarse (in which case it would have to be very muddy/heavy slurry).

Sharpening to a burr is counterproductive and works against sharpness. Most ceramic waterstones (1200 grit or below) have no trouble with many common 'supersteels' as the vast steel matrix around the carbides is soft comparatively and thus, easily cut by these ceramics.

Assuming the bond strength is not excessive they will renew themselves with fresh, unworn (and most importantly SHARP) abrasive particles which continue cutting rapidly. Once your edge has all the damage removed and the actual apex is no longer visibly reflecting light -- then you know that you have gotten the apex thin enough to apply a micro-bevel at apex.

This is where the fixed abrasives are a god-send as you can trivially bring knives to very high sharpness with even coarse plates such as the Spyderco CBN assuming you use 1- lubricant, 2 - light pressure, - edge forward strokes at slightly higher angle to grind a micro bevel, 3 - alternating strokes from one side to other/ crossing scratch patterns. All of this will tend to avoid forming a burr when actually directly grinding on the apex.

If you reverse those two categories of stone for each role (shaping vs sharpening), you have made your job much more complicated and involved and in general it will take you much longer and/or require elaborate deburring steps. With something like a simple Naniwa Multistone 1000 : one can literally grind all day with a creamy slurry created by just a few passes of a flattening plate like an Atoma and NEVER actually reach a strong burr or sharp apex.

With a CBN 400, one can literally raise a heavy and stubborn burr in seconds and spend 10's of minutes and multiple steps and stone progressions in trying to remove that burr and get a clean apex!!!

[nonstainless]

306CBN is my top favorite benchstone for about 2 years now. I used to sharpen on diamond plated stones which wear out after some use, but this CBN is bonded so it will last forever...
In 9 of 10 freehand sharpening sessions it's all I need. The two grits are well balanced, I don't chase mirror polish any more. Just sometimes I take a lower grit diamond for reprofiling.
I prefer to sharpen on 306 dry but it can be used with water as well. It's large enough for almost any blade. It's the best value benchstone you can get IMO.
Btw, don't be afraid of the burr, if someone is, then he knows little to nothing about FH sharpening.

[Traditional.Sharpening]

Btw, don't be afraid of the burr, if someone is, then he knows little to nothing about FH sharpening.

That appears to be a rather bold statement, are you directing this statement at anyone in particular?

[bbturbodad]

I used to sharpen on diamond plated stones which wear out after some use, but this CBN is bonded so it will last forever...

This is not a bonded stone, it's a plated single layer stone.

[Steeltoez83]

I've used mine a fair bit. The 400 to me appears to be holding up better than the 800 side. My stone recommendation will always be the king neo stone for entry level freehand sharpening. The silicon carbide will cut the majority of carbide types but not all of them. It is harder than ceramic. However the cbn stone will do everything but overall longevity is the concerning part. As far as using it solely to set microbevels I've not had success in my own testing trials. The edges from burr based sharpening produced more consistency in my own testing platform. And when restrictions on setting the microbevel were implemented I saw sharpness decreasing at a faster rate. Well atleast for the current testing I do. I don't have access to Cliff Stamp to discuss my findings when I used his plateau method for the 10 trials I did. The cbn stone is also very thin which also threw me for a loop bcuz I'm used to thicker stones personally. And mine has no sides labeled which is a minor annoyance.

[Traditional.Sharpening]

I've used mine a fair bit. The 400 to me appears to be holding up better than the 800 side. My stone recommendation will always be the king neo stone for entry level freehand sharpening. The silicon carbide will cut the majority of carbide types but not all of them. It is harder than ceramic. However the cbn stone will do everything but overall longevity is the concerning part. As far as using it solely to set microbevels I've not had success in my own testing trials. The edges from burr based sharpening produced more consistency in my own testing platform. And when restrictions on setting the microbevel were implemented I saw sharpness decreasing at a faster rate. Well atleast for the current testing I do. I don't have access to Cliff Stamp to discuss my findings when I used his plateau method for the 10 trials I did. The cbn stone is also very thin which also threw me for a loop bcuz I'm used to thicker stones personally. And mine has no sides labeled which is a minor annoyance.

That is interesting but perhaps you could share more information and someone aside from Cliff may have some insight?

[Steeltoez83]

I've used mine a fair bit. The 400 to me appears to be holding up better than the 800 side. My stone recommendation will always be the king neo stone for entry level freehand sharpening. The silicon carbide will cut the majority of carbide types but not all of them. It is harder than ceramic. However the cbn stone will do everything but overall longevity is the concerning part. As far as using it solely to set microbevels I've not had success in my own testing trials. The edges from burr based sharpening produced more consistency in my own testing platform. And when restrictions on setting the microbevel were implemented I saw sharpness decreasing at a faster rate. Well atleast for the current testing I do. I don't have access to Cliff Stamp to discuss my findings when I used his plateau method for the 10 trials I did. The cbn stone is also very thin which also threw me for a loop bcuz I'm used to thicker stones personally. And mine has no sides labeled which is a minor annoyance.

That is interesting but perhaps you could share more information and someone aside from Cliff may have some insight?

I don't think I was accurately measuring microbevel sharpness when I did that testing 6 or so months ago. It's on my bucket list to retry some of the knives I've done. And evaluate both results. Steels I've tested were H1, vg10, s45vn, and I think aus 10 with 13dps microbevels on a 1k super vitrified diamond stone. I'm hoping when I get back to it I see results mirror each other with both styles. Burr based sharpening is more common and produced better results from the testing I've personally done so far.

[Bemo]

I never was able to get good results using Cliff Stamps plateau method either, but I'm not the best sharpener in the world.