Best all around reprofiling stone(s) for EP?

Mr.Wizard said:
I wonder if the extreme hardness of diamond particles lets them bite deeper than similarly coarse particles of a softer abrasive, moving the corner of performance further to the right, in terms of the chart I attached.
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Absolutely!!! But the bond has a huge effect on how the stone works too. Resin is a much less aggressive bond than most, if not all, other bonds. Oh, and diamond is not all the same. The differences between mid range and high end diamond powder is hugh, as in tool life may be several times better with a better grade of diamond.

I feel that your chart isn't very accurate with diamond and harder steel, at least with my experience. I would guess the 80 grit, 160 micron, Matrix stone removes 6-8? times more metal than the 250 grit, 80 micron, Matrix stone. If you compared vacuum brazed nickel/reactive metals alloy single layer diamond stones I would bet the difference would be even bigger as the crystal size grows. This is a bond that you could get away with a 25% bond line and not be able to pull the crystal out of the bond, it would sheer in half if overloaded. I think it may be the ultimate bond for diamond performance wise, at least that I know of. With this bond the limiting factor would be crystal strength.
 
Diemaker said:
I would guess the 80 grit, 160 micron, Matrix stone removes 6-8? times more metal than the 250 grit, 80 micron, Matrix stone. If you compared vacuum brazed nickel/reactive metals alloy single layer diamond stones I would bet the difference would be even bigger as the crystal size grows. This is a bond that you could get away with a 25% bond line and not be able to pull the crystal out of the bond, it would sheer in half if overloaded. I think it may be the ultimate bond for diamond performance wise, at least that I know of. With this bond the limiting factor would be crystal strength.
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Please correct me if I'm wrong. For bonded 80-microns->160-microns math looks like this:
Average weight of particle - 8x;
number of particles in volume (for equal diamond density) - 0.125x;
average performance of particle 2x-4x; (AFAIK this factor has its own diminishing return for ultra coarse grits)
area diamond density 0.25x-0.5x;
performance of area 0.5x-1x;

To achieve 6x-8x increase, the diamond density of 160 microns should be theoretically 8x-16x more than 80 microns.

For coated abrasives, the diminishing return is even worse - performance of area 0.25-0.5x for 80-microns->160-microns.

It's just theoretical, I could be wrong.
 
Sorry but I don't know the theory, I just make stuff and try it. See where it succeeds or fails, modify, and try again. Keep doing this until it works or you run out of options, or money.

I know it is not the same but I make most of the tools I use to cut stone and this does increase my understanding of how diamond behaves when cutting stuff. I have found the difference between 40, 60, and 80 grits is F&@KING ASTRONOMICAL!!!!! Tool life changes between the three are up to 1000 times longer with one grit vs the other. Diamond is some damned interesting stuff! Get it right and it lasts a very, very, very long time. Get it wrong and poof, it's gone. At least with powered grinding.

Konstantine, do your numbers take into account that the larger diamond crystals can take larger cuts, i.e. larger chips?
 
Diemaker said:
Sorry but I don't know the theory, I just make stuff and try it. See where it succeeds or fails, modify, and try again.
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I think we can all be glad you are doing this work; it seems like the way forward. I realize there are aspects that you will want to keep proprietary, e.g. formulation, but would you consider sharing your findings to the extent possible? For example perhaps create tables of material removal rate by pressure and grit for several different common knife steels?
 
Mr.Wizard said:
I think we can all be glad you are doing this work; it seems like the way forward. I realize there are aspects that you will want to keep proprietary, e.g. formulation, but would you consider sharing your findings to the extent possible? For example perhaps create tables of material removal rate by pressure and grit for several different common knife steels?
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You do realize that David has a day job, don't you? :p
 
I am just a one person shop doing production stone switchplates, some production parts for EP and the Matrix stones. When I have some free time I am trying to get some new products into production. My tests are a lot less scientific, more of the make something I want to use way of doing it. The big secret is the bond, which is probably true with most stones. The abrasive is pretty much what you buy, not a lot to play with really. The bond is what makes or breaks a stone, and the choices are vast. I have been working on this since around 2003 so I have tried a lot of different materials for the bond, and still playing with it. I am open about what abrasives I use and what size they are but beyond that the formulation, which includes the process, is something I want to keep to myself. I don't want to give any possible competitors any ideas you know. I have played with alox, sic, boron carbide and diamond as the abrasive and diamond is by far the most aggressive. I haven't been interested in CBN because it isn't as hard or aggressive as diamond and costs about 10 times more, in line with polycrystalline diamond.

I think the best way to understand a new set of stones is to try them, that is why I have a pass-around kit available. So you can try them out for a few weeks and see for yourself if you like them or not. I can add some prototypes using different abrasives if you want to play with different things. Wish I had a set of Venev stones to add to the kit for comparison purposes, it would really add to the value of the kit.

Machine just stopped so this is it for now, I will check back later tonight while epoxying switchplates.
 
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NORTHWEST_KNIFE_GUY said:
Not my channel, this is spadeknifeworks.
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One of the better sharpeners out there. I learned alot from his videos and ig live feeds in general he helped improve my level little by little. You don't really get to learn this kind of detail from other tutorials imho. If you have other sharpeners sharpen your knives, you notice alot of general sharpeners 'mirror' edges arnt that mirror but more scratchy and foggy mirrors due to no technique like the one he followed in the video you posted above. Nate is a true inspiration.
 
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Mo2 Mo2 At 11:47 in the video above he appears to knock a big chip out of the edge at the tip by using too much pressure and being sloppy, running off the tip with the stone. I've done that too but I wouldn't call it inspirational. Oh well, nobody is perfect.
 
Mr.Wizard said:
Mo2 Mo2 At 11:47 in the video above he appears to knock a big chip out of the edge at the tip by using too much pressure and being sloppy, running off the tip with the stone. I've done that too but I wouldn't call it inspirational. Oh well, nobody is perfect.
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Lol yea I mean everyone makes mistakes. It happens. I didn't see any huge chip and it was getting re profiled anyways. So really no big deal, and you can't really subject one video with a minor issues as negative as a whole, which it sounds like your suggesting by your reply. The end results if you look at them are excellent and better than alot of sharpeners (I'm not suggesting he is the best) . I'm just suggesting the content he's shared with me was inspiring and helpful to me. If you don't feel the same :shrug: .
 
Mo2 Mo2 Sorry, I was just being grumpy. I started watching it with a critical eye (hoping to learn) and I didn't like the short scrubbing strokes as that would wear my stones unevenly, so I guess I was looking for an excuse to discount his technique and the tip slip was it. Thanks for the polite reminder to behave. :)
 
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Mr.Wizard said:
Mo2 Mo2 Sorry, I was just being grumpy. I started watching it with a critical eye (hoping to learn) and I didn't like the short scrubbing strokes as that would wear my stones unevenly, so I guess I was looking for an excuse to discount his technique and the tip slip was it. Thanks for the polite reminder to behave. :)
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I mean you could do long strokes in a similar fashion. It's just what he does, everyone's different. And he pays for it and ends up buying alot of replacement stones often iirc. In any case doing a video, talking and sharpening isn't always easy too.

I use bonded stones and use a bit longer stroke myself so they wear more even. Even so, I can refresh them flat again cause there bonded. Which saves me money.
 
Mo2 said:
I mean you could do long strokes in a similar fashion. It's just what he does, everyone's different. And he pays for it and ends up buying alot of replacement stones often iirc. In any case doing a video, talking and sharpening isn't always easy too.

I use bonded stones and use a bit longer stroke myself so they wear more even. Even so, I can refresh them flat again cause there bonded. Which saves me money.
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I think he mentioned that he purchased 10 or so in the past year. But hey, if you're sharpening tons of knives and doing so at a profit for customers, it's not a ton of expense if they're the CKTG version.

Personally, I think he did a quite reasonable job of communicating while sharpening and keeping it all together.
 
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