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Fallkniven DC4 Ceramic Side Grit

Discussion in 'Maintenance, Tinkering & Embellishment' started by Papilio, Sep 27, 2019.

  1. Papilio

    Papilio

    25
    Sep 6, 2019
    It's a shame that Fallkniven does not give an accurate grit for the ceramic side of their DC stones. I searched the forums and did not find an answer, but maybe I did not searched accurately enough (I have the suspicion that I am not very good at that). Sorry, if that question has been already answered.
    When the stone was new it was very rough (as described on the packing). Now the ceramic side is much finder and quite smooth, but this took a long time and some lapping on a coarse stone. The surface looks different. I don't have a photo what it was like at the beginning.
    [​IMG]


    Now I can get a shaving sharpness out of that stone.
    I also have a Victorinox Dual Knife Sharpener and an EZE-LAP Hone & Stone Super Fine. The first (ceramic pull-through) should be ~1000 FEPA, the last 1.200 ANSI. Both give a sharp edge, but not that sharp than the DC4s ceramic side.
    I think the grit is finer than 1000 FEPA (3000 JIS), but is it closer to 3000 or 6000 (unofficial statement from Fallkniven somewhere on the internet)?
    What do you think? what are your experiences with the DC4? Or do you even think it is not even that fine?
    Is the ceramic only that smooth at the surface (through lapping) and will get rougher when the smooth part wears down through sharpening?
     
    Last edited: Sep 27, 2019
  2. The lapping on the coarse stone is essentially the only thing determining at what grit it's currently working, and there's really no pinpoint accuracy in gauging exactly what that would be. The lapped result will ALWAYS be considerably finer than whatever was used to lap it. For example, some here have found that using 60-80 grit loose silicon carbide grit to lap a hone like a medium Spyderco ceramic comes fairly close to emulating it's factory finish (often described somewhere in the 600-1200 estimated 'grit', depending on what standard it's compared to). So, depending on what grit is used to lap it (hardness of grit, shape & size of grit, how the grit is bound, as in a stone, or if it's loose grit, etc), the final working finish will vary all over the place, as with any sintered ceramic hone lapped in a similar manner.

    This is also true with the factory finishes on these hones, as it's all about how they're finished on the surface. The size of the raw grit used to make the hone isn't much of a factor beyond that. For example, Spyderco uses the same size & type of raw grit material for each of their hones in medium, fine and ultra-fine 'grit', with the only working differences being the binder material (for the medium 'gray') and surface finishing of each.

    My DC4 was also very rough from the factory. Over time, I've lapped it a couple or three times, using varying means. It's now working at a much smoother/finer finish, though still removing steel very well.

    Ordinarily, the working smoothness or finish of the hone will gradually get finer and/or more polished with continued use & sharpening on the hone. This is due to the gradual wear (glazing, burnishing, polishing) of the surface grit's cutting edges over time. These hones don't ordinarily shed much old grit to expose fresh grit under use. Lapping is generally the only thing that'll restore it to a coarser performance, depending on how the lapping is done and with what media.
     
    Last edited: Sep 27, 2019
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  3. FortyTwoBlades

    FortyTwoBlades Baryonyx walkeri Dealer / Materials Provider

    Mar 8, 2008
    Sintered ceramics are usually made with a range of grits, with the bulk averaging around 3┬Ám, but that will vary depending on the particular formulation. As such, they don't really have a true grit rating in the way we usually think of it. The different grit sizes aid in the sintering process. The resulting finish produced by the stone, however, is worlds different than that of conventional vitrified or resin bond stones or coated abrasives, and is mostly dependent on the surface finish of the stone.
     
    mycough likes this.
  4. Papilio

    Papilio

    25
    Sep 6, 2019
    Thanks for both answers. Well, there is so much I have to learn about sharpening. But on the other hand I should take it easy. A sharp blade is what counts. I should stop thinking too much about stones, grit (charts) and what ever. That kills the fun.
    The Fallkniven DC4 is often mentioned when it comes to pocket sharpening stones. Therefore I thought it would be a fair choice. Maybe my next stone is one with a true grit rating. Just to be sure I don't overact.
     
  5. Most of it depends on which steels you're sharpening and what type of edge finish you want, such as coarse & toothy vs. high-polished, or somewhere in between those extremes. Described specifically in those terms instead of in grit numbers, you could get a lot of good recommendations here for stones to try. Sintered ceramics are always kind of a toss-up for the reasons mentioned, and most of them will tend toward more refined and/or polished finishes (though still hard to nail down exactly), instead of very toothy, with Fallkniven's very coarse/rough factory finish being the very odd exception, from what I've seen.
     
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