Update on Metallic Bonded CBN stones.

[wade7575]

I have had my Metallic Bonded CBN stones for a while and I have not had the chance to use the 50 grit or the 120 grit much at all as I have not had a need to use a stone that low in grit and I was given some planer blades to sharpen by a friend and they were in pretty ruff shape so I thought why not try out the 50 grit CBN stone and I must say it must be the most useless stone I own and have ever used it's horrible just horrible.

The 50 grit stone seemed to just skate right over the metal and not really remove much at all and just seemed to scratch the edge up really good where the stone had been run over and I think the problem it that the CBN particle's are so big that they just skate over the metal and a grit this lower may be better used like a sanding block or something like that but not for sharpening knives and all I can say is I will never buy another 50 Metallic Bonded CBN stone again.

Now however the 120 grit stone was a totally different story it cut threw the metal very very fast and did not tear up the metal even if I Apex the edge using push pull stroke's and it should be noted I had to use a bit of pressure to get the 120 to cut but once I found the right pressure to use it really cut fast and I would say 3 to 4 times faster then the 50 grit if not faster then 3 to 4 times the speed,I also tried using extreme pressure on the 50 grit and it still did not cut any faster.

I also found that the 120 and the rest of the Metallic Bonded stones seemed to cut faster dry but that could be because I could see the metal filing's building up on the edge like little hairs.

If you are thinking about investing in these stones do yourself a favor and steer clear of the 50 grit and any grit higher then the 50 grit I would say go for it for sure as I have right up to their 8000 grit stone and from the 120 to 8000 they all work very well and I have no reason to complain about them at all.

 

[wade7575]

I forgot to mention as well that the Venev 120 does not remove metal as fast as the Metallic Bonded CBN stone and neither does the Venev 80 grit stone I have some 60 grit Venev's on order but I'm not counting on them to remove metal as fast as the 120 CBN stone but you never until you tried and for that I will have to wait.

 

[mycough]

Good info, thanks for your report. A lot of good stuff in your postings, I am sure many have benefited from research.

Russ

 

[Mo2]

I'm getting the diamond version with the hapstone m2 kickstarter.

Grits from 100 to 2500.

 

[wade7575]

I don't have a 100 grit in these stones but I think it would still be a good stone if someone were to pick one up.

 

[bucketstove]

I have had my Metallic Bonded CBN stones for a while and I have not had the chance to use the 50 grit or the 120 grit much at all as I have not had a need to use a stone that low in grit and I was given some planer blades to sharpen by a friend and they were in pretty ruff shape so I thought why not try out the 50 grit CBN stone and I must say it must be the most useless stone I own and have ever used it's horrible just horrible.

The 50 grit stone seemed to just skate right over the metal and not really remove much at all and just seemed to scratch the edge up really good where the stone had been run over and I think the problem it that the CBN particle's are so big that they just skate over the metal and a grit this lower may be better used like a sanding block or something like that but not for sharpening knives and all I can say is I will never buy another 50 Metallic Bonded CBN stone again.

Now however the 120 grit stone was a totally different story it cut threw the metal very very fast and did not tear up the metal even if I Apex the edge using push pull stroke's and it should be noted I had to use a bit of pressure to get the 120 to cut but once I found the right pressure to use it really cut fast and I would say 3 to 4 times faster then the 50 grit if not faster then 3 to 4 times the speed,I also tried using extreme pressure on the 50 grit and it still did not cut any faster.

I also found that the 120 and the rest of the Metallic Bonded stones seemed to cut faster dry but that could be because I could see the metal filing's building up on the edge like little hairs.

If you are thinking about investing in these stones do yourself a favor and steer clear of the 50 grit and any grit higher then the 50 grit I would say go for it for sure as I have right up to their 8000 grit stone and from the 120 to 8000 they all work very well and I have no reason to complain about them at all.

Hi,
If stone is skating that means the pressure is too low.
What is "extreme pressure" on the 50 grit?
Have you tried using 50 grit behind the edge (on the flats), Where you can really crank up the pressure?

If you look at the stone, at the stone surface, at the diamonds themselves, how are they oriented? Mostly pointy ends sticking out, or mostly flat or half and half?

 

[Diemaker]

I just tried out a set of the Venev diamond stones and found the same thing. The F80, 180 micron, stone was too coarse and didn't remove metal nearly as fast as the F150, 80 micron, stone. This was grinding on a decent 440c blade. There gets a point where making the abrasive grains bigger deters metal removal, IMO.

 

[wade7575]

I always try to share anything I find out or figure out because it can be such pain if you are not very good with your hands and need to do mods to stuff,I did a lot of RC Cars and Boat's when I was younger building boat's that would go 60 to 70 MPH and only be 3 feet long and did a lot with the RC Cars building stuff as well and I also did a lot of soldering for a lot of guys that were into RC because they did not have the knack to not over heat something or would tear a copper foot print on a board because they did not remove all the solder and other problems plus being into the hobby's I've has taught me that sometimes you can use product's for stuff they were never intended,I use a product called Krud Kutter and I use the original to remove flux from a board if I have had to do any soldering to it and I find liquid flux works the best but it also contains Rosin in the flux witch is pine pitch and the only thing that cut's it fast is gasoline from what I understand if you do not want to have to buy special stuff to remove it,the Krud Krutter I just mix 15 to 20% with water then let it sit for 10 to 20 minutes and then brush the flux off most people on the electronic's forums thought I was a nut job when I told them about it until other people starting trying it and said you can re-use it 20 to 30 times if not more then I was genius.I should also mention that Krud Kutter works so well you can even use cold water.

It's the same thing with Bar Keepers Friend I seriously owe that person a million thank you's because that stuff work's better then anything else I tried,I will say this however I find the powder works great and liquid for me only works unless it has sat long enough for the white powder crap to get hard in the bottom of the bottle and you get more of just a clear liquid then it works just like the powder put it on the stone rub the stone 3 or 4 times and your done if the liquid has not changed for me and it has not gotten hard in the bottle I find letting it sit for 10 minutes does not do crap.

Good info, thanks for your report. A lot of good stuff in your postings, I am sure many have benefited from research.

Russ

 

[wade7575]

I think the diamonds are cheaper not sure why I know it may have something to do with the way CBN is made that makes it more money to produce,I know from what I have read that CBN is made pretty much the same way as synthetic diamond's but they do something a bit different,it won't matter for the kind of sharpening we do but diamonds synthetic or not get soft when they got hot and do not cut as fast but CBN on the other hand witch is almost as hard as diamond can withstand more heat then diamonds before it start's to get soft and break down and not cut as fast if your wondering where the heat's coming from it's coming from the CBN used in grinder type application's.

When you order your Hapstone M2 and if it's from Gritomatic order some Silicon Carbide Powder and you only need 2 grit's and these are the instructions on how to use them.

Use F120 Silicon Carbide Powder for stones 50,120,240,400 grit and use F400 Silicon Carbide Powder for 600,800,1200,4000,6000,8000 grit stones,I have not tried this but a friend of mine online from another country that knows his stuff and had been using these for many year's in a machine shop swear's by doing it this way and you can compare the grit's and get a few more powder's just warned that the goal is to use a powder that is smaller then the diamond or CBN particle's so the grit goes between the diamonds and CBN.

Also use a peace of Tempered glass and use water with the powder to make a paste,also be warned and take this next part more then extremely serious do research because I forget where I read but with Silicon Carbide that is really fine and that can get air born and float around it can and most likely will give cancer if you breath it in enough if your not sure just use a rag over your face and a teaspoon to get it out of the bottle and just move slowly and you will be fine once it is mixed with the water then you have nothing to worry about if I can find where I read it I post what the grit's are that you have to really start to be careful with.

When using the slurry of powder use a figure pattern and you need to use pressure but not very much at all and never use a lot of pressure on any Metallic Bonded CBN or diamond my friend told me once the stone has been refreshed and if you have not gone over board you can use pressure when using them and lot's of but not when removing the Brass and Copper that's holding it in place,the reason why that is is because you can remove the Brass and Copper faster then you think you would and the CBN or diamonds will just fallout and he has had it happen,if your not sure what's going on and if you have taken enough off when you refresh your stones rinse the stone and feel it and look at it with a jeweler's loupe that's the best way to tell.

I'm getting the diamond version with the hapstone m2 kickstarter.

Grits from 100 to 2500.

 

[wade7575]

I was pushing as hard as I could without damaging my guide rod and I'm fairly big and strong man and I was giving all I had for about 30 to 40 seconds in the same spot and the stone didn't do Dick.

I've done something thinking on this as the best way I can describe what I think is going on because most people think more is better just like diamond paste witch is another subject but I will say if you talk to a straight razor guy who really knows his stuff he will say use 4 to 10 Carat paste max anything higher for a straight razor is bad news because the diamonds tend to clump together and it's not a problem for knife guys but for guys who are putting the edge against their face it is.

I live in Canada where we get a good bit of snow and a lot of people who don't have a clue think oh look at that truck with the really wide that thing must handle great in the snow and that is completely wrong and what most people think is the more tire on the road the better the grip but what they forgot was to take into account pounds per-square inch with is reduced,when front wheel drive car's first came out they were smaller car's with narrow tire's and there was more weight over the drive wheel's witch mean's they cut threw the harder snow better and also grip better because the pounds per-square inch were increased and I can tell you I used to go with a older gentleman I used to work for when I was younger on his mail route and he had a front wheel drive Toyota and we could park on the hill out front of the Post Office and always make it up the hill the rear wheel drive cars always struggle and were left spinning their wheels and cursing a lot before they made it up the hill from a dead start after many attempt's.

I think what's going on is the same thing and trust me I tried trailing stokes I tried push pull sweeping and stroking as fast as I could and as long as I could until my shoulder was on fire and as I said before the result was sweet Dick all and I know your not supposed to just grind away in the same spot but the planer blades I was told they did not care if I could fix them or not because they were rusty and just plain ruff and were intended to go for scrap and that's why I was testing the stone like that because I thought something most be wrong and there is and it's that stone sharpening knives in my opinion and under no circumstance will I ever buy a another 50 grit Metallic Bonded CBN stone and if one is gifted to me and I try it again I will be throwing it out or selling it if it proves to be just as useless.

Hi,
If stone is skating that means the pressure is too low.
What is "extreme pressure" on the 50 grit?
Have you tried using 50 grit behind the edge (on the flats), Where you can really crank up the pressure?

If you look at the stone, at the stone surface, at the diamonds themselves, how are they oriented? Mostly pointy ends sticking out, or mostly flat or half and half?

 

[wade7575]

I think your dead on and I think it also has a lot to do with what I said above the pounds per-square inch are less and the abrasive just skate's right over the surface,I find the Venev 80 grit to work not as fast as the 120 Metallic Bonded CBN but it still worked for me,I will also say that the 120 grit does not tear up the edge at all when compared to some less coarse water stones I have used that were a little higher in grit but not much I forget the brand but the 120 woks better then most would think for not making the edge look at it was put threw a grinder at a million rpm's,I'm wondering if the Brass and Copper have a bit of a buffing or smoothing affect while sharpening.

I just tried out a set of the Venev diamond stones and found the same thing. The F80, 180 micron, stone was too coarse and didn't remove metal nearly as fast as the F150, 80 micron, stone. This was grinding on a decent 440c blade. There gets a point where making the abrasive grains bigger deters metal removal, IMO.

 

[bucketstove]

I just tried out a set of the Venev diamond stones and found the same thing. The F80, 180 micron, stone was too coarse and didn't remove metal nearly as fast as the F150, 80 micron, stone. This was grinding on a decent 440c blade. There gets a point where making the abrasive grains bigger deters metal removal, IMO.

Hi
Really? The coarser stone was 3-4 times slower than the finer stone? Even under high force ?
What about the stone surface, are the exposed diamonds mostly pointy or mostly flat? How hard were you pushing?

 

[bucketstove]

I was pushing as hard as I could without damaging my guide rod and I'm fairly big and strong man and I was giving all I had for about 30 to 40 seconds in the same spot and the stone didn't do Dick.

Hi,
What is that like (1lb? 3lb? 5lb? 10lb?) Sorry, i dont know about guiderods...

What about looking at the exposed grits, are they mostly flat or mostly pointy?

I think what's going on is the same thing and trust me I tried trailing stokes I tried push pull sweeping and stroking as fast as I could and as long as I could until my shoulder was on fire and as I said before the result was sweet Dick all and I know your not supposed to just grind away in the same spot but the planer blades I was told they did not care if I could fix them or not because they were rusty and just plain ruff and were intended to go for scrap and that's why I was testing the stone like that because I thought something most be wrong and there is and it's that stone sharpening knives in my opinion and under no circumstance will I ever buy a another 50 grit Metallic Bonded CBN stone and if one is gifted to me and I try it again I will be throwing it out or selling it if it proves to be just as useless.

I'd expect after ~P200/~70micron , that the speed gains from coarser grits would slow down (no longer linear speed gains , see Characteristics of Abrasive Particles and Their Implications on Wear | InTechOpen ),

but a full on reversal?
That sounds like the grits are dull, mostly flat and not pointy,
and the stone is indeed completely pointless because
it cannot be used as for the purpose it is being sold for
and they need to stop selling it and issue refunds

 

[wade7575]

I use a Tsprof K02 system and if I pushed any harder I most likely would have damaged something whether it would have been a bent planer blade or something broken on my system I don't know but I was not going to push any harder because it would not have longer and I would have been doing some bitching I'm sure as far as the pressure I can say other then it was a lot and closer to 40 to 50 lb's would be my guess if I had to if not more and I would be surprised if it was,I did not use this extreme pressure for a really long time because I knew with that much pressure after 10 to 15 full push pull strokes you should have been at least been able to see something and you pretty would never know by looking at that I ran a stone over that section,I would compare other stuff I tried like I said before about doing really fast push pull strokes I have to compare that to watching an idiot using a file trying to file brass and not getting anywhere and watching the guy go like hell for hour until he's about ready to have a stroke and then he realize's that the file was just dull it should have been thrown out long age.

The CBN is pointy and sticks out a good ways from the Copper Brass you'd be surprised how ruff and how far past it stick's out,if I remember they use Poly CBN and not Mono,I'm upset aboutthese stones it's just a learning thing still as we have just started to learn more about them and I can't complain because I get thrown stuff often from Konstantin from Gritomatic to test and the first stone I got thrown was a Metallic Bonded CBN and when I got my full set I passed it along to a youtuber I know and who is a good guy and his channel is Canadian Cutting Edge I threw it to him because he can not work because Jake was born with problems with his leg's and he will only get worse as time goes on,I know for him even short email's he has to read 3 or 4 times from the pain and meds before he get's the jist of it sometimes from what he has told.

 

[wade7575]

B bucketstove I was thinking and I think a better way to explain what's going on with the 50 grit stone is to think of it like 2 knives 1 a Japanese Chef knife sharpened at 9 degree's per-side and a hunting knife sharpened at 55 degree's per-side and of coarse the Japanese chef knife is going to be the better slicer and the hunting knife is going to have to be used more like an ax because t's edge is just to blunt to be effective.

I think it's the same problem with the 50 grit stone the CBN particle's are so big they are the blunt edge on the hunting knife and they are not suited to slicing threw the steel.

 

[bucketstove]

I use a Tsprof K02 system and if I pushed any harder I most likely would have damaged something .. planer blade .. as the pressure I can say other then it was a lot and closer to 40 to 50 lb's would be my guess ... The CBN is pointy and sticks out a good ways from the Copper Brass you'd be surprised how ruff and how far past it stick's out,if I remember they use Poly CBN and not Mono,I'm upset aboutthese stones

Hi,
Thats just weird.
Does lube change anything? Oil?
What are these planer blades made from?
Have you tried contacting ..?gritomatic?.. ? I'd be curious to hear what they have to say about cutting speed

 

[FortyTwoBlades]

I think the diamonds are cheaper not sure why I know it may have something to do with the way CBN is made that makes it more money to produce,I know from what I have read that CBN is made pretty much the same way as synthetic diamond's but they do something a bit different,it won't matter for the kind of sharpening we do but diamonds synthetic or not get soft when they got hot and do not cut as fast but CBN on the other hand witch is almost as hard as diamond can withstand more heat then diamonds before it start's to get soft and break down and not cut as fast if your wondering where the heat's coming from it's coming from the CBN used in grinder type application's.

When you order your Hapstone M2 and if it's from Gritomatic order some Silicon Carbide Powder and you only need 2 grit's and these are the instructions on how to use them.

Use F120 Silicon Carbide Powder for stones 50,120,240,400 grit and use F400 Silicon Carbide Powder for 600,800,1200,4000,6000,8000 grit stones,I have not tried this but a friend of mine online from another country that knows his stuff and had been using these for many year's in a machine shop swear's by doing it this way and you can compare the grit's and get a few more powder's just warned that the goal is to use a powder that is smaller then the diamond or CBN particle's so the grit goes between the diamonds and CBN.

Also use a peace of Tempered glass and use water with the powder to make a paste,also be warned and take this next part more then extremely serious do research because I forget where I read but with Silicon Carbide that is really fine and that can get air born and float around it can and most likely will give cancer if you breath it in enough if your not sure just use a rag over your face and a teaspoon to get it out of the bottle and just move slowly and you will be fine once it is mixed with the water then you have nothing to worry about if I can find where I read it I post what the grit's are that you have to really start to be careful with.

When using the slurry of powder use a figure pattern and you need to use pressure but not very much at all and never use a lot of pressure on any Metallic Bonded CBN or diamond my friend told me once the stone has been refreshed and if you have not gone over board you can use pressure when using them and lot's of but not when removing the Brass and Copper that's holding it in place,the reason why that is is because you can remove the Brass and Copper faster then you think you would and the CBN or diamonds will just fallout and he has had it happen,if your not sure what's going on and if you have taken enough off when you refresh your stones rinse the stone and feel it and look at it with a jeweler's loupe that's the best way to tell.

You seem to be a little confused on a few points. It's not so much that diamonds "go soft" at high temperature, but that they will "leak" carbon at high heat and in many industrial grinding applications the carbon will leach into a ferrous workpiece, which causes all sorts of problems. CBN does not do this, which is why it's used for grinding ferrous metals, while diamond power abrasives are generally used on ceramics since they're harder than CBN is.

As far as silicon carbide goes, you're probably thinking of how certain older methods of silicon carbide production could result in the formation of carbon nanotubes that can cause mesothelioma similar to asbestos. This was a risk mostly for industrial workers in plants still using that particular method of production, and it's of little possible risk to consumers, especially since most silicon carbide is no longer produced via that outdated method. That being said, inhaling dust of any kind isn't good for you, so try not to breathe it in if you can avoid it.

 

[Diemaker]

Hi
Really? The coarser stone was 3-4 times slower than the finer stone? Even under high force ?
What about the stone surface, are the exposed diamonds mostly pointy or mostly flat? How hard were you pushing?

I would say the F150 was around 3 times faster than the F80, on my CRKT 440c blade. I pushed hard enough, say 1 lb, that if it was going to work it would have. Not being my stone and being resin bond I was cautious, I didn't want to have to dress it because I scraped the diamonds out. I am pretty sure the stone was in good shape and didn't need dressing. I did look at it under the microscope and took pictures of both the F80 and F150. The surface is very dark and hard to see the diamonds in it as they show up almost black. From the reflections on the facets I would say they were in good shape with pointy tips exposed. I think what happens is the crystal can only dig into the steel so far, no matter how large it is. With the coarser grits you get fewer crystals per inch exposed so that is why they slow down. Slightly smaller crystals will cut just as deep but since there are many more per square inch that stone will cut faster. Exactly what is optimum depends on the steel and how hard it is. I would think the harder or more wear resistant the steel the finer the grit should be, just a theory, I could be wrong.

 

[wade7575]

I know from what I read the 50 grit is supposed to have double the of CBN in it because the particle's are bigger and I guess they feel there would be more space between the particle's then you would want.

 

[wade7575]

I talked to Konstantin the owner of Gritomatic and recommended he stop selling the 50 grit and he asked me how much CBN was sticking out from the surface and thought the stone needed to be refreshed and that simply is not the case there is a ton sticking out and t's god and far and I can see that with my naked eye never mind a jewelers loupe,I just use water with these stones or sometime's dry as well,the planer blades are just normal planer blades you buy from the hardware store and they are for a cheaper brand of planer that Canadian Tire sell's under their own brand.

Hi,
Thats just weird.
Does lube change anything? Oil?
What are these planer blades made from?
Have you tried contacting ..?gritomatic?.. ? I'd be curious to hear what they have to say about cutting speed