Move from water stones to diamonds or not?

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This topic contains 14 replies, has 4 voices, and was last updated by  Edmund 9 months, 3 weeks ago.

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    I really need to beef up my sharpening set up. Have only used water stones for over 15 years, but, as a lazy hobbyist who does more fooling around than cutting wood, its like a blade or two in a week kind of usage. Currently use 1000 and 4000 “grit” water stones and a strop. Stone flattening done using sandpaper on glass which is no fun. Now, due to the “Paul effect”, I’ve been spending more time in the shop and even otherwise the coarser 1000 stone is all but worn out. Looks like this may be the time to move away from water, or to embrace it fully.

    I was almost getting ready to move to diamonds. But then came across some threads here like
    where @ed talks about returning to water stones and @etmo endorses it.

    I like water stones as they cut fast. But hate the mess and the need to flatten them — discovered the latter the hard way when all my blades started developing a significant camber 🙂 I sometimes use jigs, but like to free-hand (though haven’t perfected it as yet). Free hand honing is not easy with water stones—at least not for me. Have to just pull, lift and pull or risk gouging the stones. I recall most folks here highly encourage to perfect free hand honing skills.

    So would it be better to replace the worn out water stone and possibly get a higher grit one too (say 8000 or 10k?) and also get some kind of flattening stone? Or switch to diamond stones? The latter is not cheap, so want to be sure before taking the plunge. Seeing Paul’s videos, diamonds are tempting, though.

    Sorry about the long post. I’m so conflicted about this one. Really need some advice. If sticking with water stones, what kind of flattening stone would be preferred?


    • This topic was modified 9 months, 3 weeks ago by  Selva.


    My favorite flattening stone is a coarse DMT diamond plate. That way, I take advantage of the superior flatness of the DMT plate, and still get the superior cutting speed of the water stones.

    I’m in a trial phase of a new-to-me flattening method recommended by a professor at the woodworking college. Kind of a “flatten as you go” system, which is like sharpening — sharpen more so you need to sharpen less.

    Instead of sharpening a number of tools, then having to flatten significant hollows in all the stones, I’ll sharpen a tool (or maybe twp if it’s just a small number of strokes each) on stone X, then flatten stone X and move on to my next step, whatever it is.

    That way, the stone is still very close to flat, and still quite wet from the soaking, so flattening both sides takes maybe 15 seconds total. Do it submerged in a bucket or sink, and the diamond plate runs across the stone very easily, the swarf washes away immediately, and flattening happens in no time. The dark smudges of metal embedded in the stone from the sharpening serve as the pencil marks you’d otherwise make to assure you that you’d flattened the entire surface.

    This has the added bonus of giving a more perfect surface for the next tool to touch that stone, rather than each successive tool getting an increasingly out-of-flat surface.

    It’s early days, the jury is still out and all that, but so far it seems a viable option.

    To answer your other questions, yes, I’d stick with the water stones, but it has nothing to do with price — a good stone is just as expensive as a DMT plate. It’s the speed for me. Like I said in the post you referenced by ed, I just can’t have sharpening be some horrible chore that I try to avoid, it has to be very effective and fast, so I’m never hesitant to do it. Hand tools present enough challenges even when they’re nice and sharp; dull is simply not an option.

    As far as a higher grit, that’s up to you. The surface you get straight off a Naniwa Chosera Pro 5k or the SS2 6k is good enough for quite a few things in woodworking, and better than necessary for a surprising number of things. But in my limited experience a higher grit edge lasts longer, cuts easier, and gives superior results, so can be said to be present a good ROI for the time and money spent. So I split the difference. For things like a mortise chisel or a scrub plane blade, that don’t touch show surfaces, I won’t go to the highest grits, but for my smoother, or any tool that does touch a show surface, I have been going all the way up.

    Other factors to weigh when deciding about higher grits are things like the nature of the project — a jewelry box needs to have a dead nuts perfect surface, but a saw bench done in oak, not so much. If you work with a lot of crazy jungle woods, figured grain, etc you’ll also appreciate the higher grits. I’m making some gift boxes for the holidays using black limba, and it is a train wreck of a wood if your tools aren’t sharp — the slightest hint of dull and the end grain crumbles like a dry cookie.



    I don’t think you need to go beyond about 1200 grit, I sharpen pretty often on my diamond stones, it takes about 3 minutes max, then strop it and with aluminium oxide and it’ll end up at about 16000 grit, it’s incredibly time efficient, and I don’t plan on changing to anything else.



    Thanks for the responses. Much appreciated.
    @etmo “Flatten as you go” sounds an excellent idea especially for the kind of light work I do. My current approach of waiting till its too late leads to a major pain as I end up scrubbing for ever to get the stone back to flatness.

    Probably a mistaken concern, but I was reluctant to get a coarse diamond plate as a flattening stone, for the fear that working on the abrasives in the water stone may wear out the former pretty fast. But with flattening often (and if it takes only ~15 seconds as you say), less worried about that.

    I said cheaper because King stones have been good enough for me so far. Pricier stones may cut even faster but not a big advantage for a light user like me? Saying this with very limited experience comparing stones only at some sharpening workshops.
    In fact, if I forgo diamond stones that frees up $$ and can indeed get a couple of Imanishi or even Sigma Power Select stones.

    @btryeman : For my purposes I’ve been very happy with the edges from 1000 + 4000 water stones plus optional stropping, so I totally agree going up to 1200 mesh diamond and strop may be plenty enough. Never worked on figured wood.

    Anyway, was almost certain to swing by local Lee Valley store this evening for water stones and something to keep them flat, but your response reminds me why I wanted to go diamonds all the way. Even if the flattening chore is brought under control, the general messiness of water stones and the ease of gouging them are two serious drawbacks. Yet, its like the devil I know a bit vs whoever..

    For now resetting back to the “sleep over it another weekend” mode.




    @selva my day to day sharpening is done on diamond plates. I started with water stones. Nothing cuts faster, but I got fed up with the mess and switched to the diamond plates. When I said I was going back to water stones, that was for flattening the backs, which is impossibly slow on diamond plates. If I used a lot of A2 steel, I’m not sure whether I’d use water stones for that purpose, but I avoid A2, so it’s not an issue except for a couple of tools.

    As for flattening water stones with diamond plates, DMT’s claim is that this ruins the plates. They do sell one plate especially designed for flattening water stones that, in some way, is robust enough for that purpose. Of course, it is very expensive.

    If you stay with water stones, have a look at the Sigma Power II stones, e.g., via Lee Valley. The King stones cut well, but they are soft and dish quickly.

    One final comment: If you’re going to sharpen with Paul’s method and thin western irons, water stones can be a challenge. I’ve done it, but you are almost guaranteed to dig into the stone every now and then and leave a ding. That won’t happen with a honing guide. I’ve never been taught the Japanese method, but my guess is that their irons are much thicker and they maintain full, flat contact with the bevel while making small circles, so there’s little chance of digging in (once you master it).



    @ed Thanks a lot for the response. You cover almost all of the points that were conflicting me. Especially the fact that you did not go back to water stones for routine sharpening is going to influence my decision in a big way. I was confused by the earlier thread on “Back to Water Stones”.

    I’ve no A2 blades (only O1 and PM-V11) and only a couple of Japanese blades which could be the reason why cheap King stones have worked fine for me.

    Aha, so my fear about ruining the DMT DiaSharp plates when used for flattening is real. Just checked the LV catalog: DMT DiaFlat lapping plate is more than double the price.

    I totally get the comment about digging into the stone if both pushed and pulled as Paul teaches. Have done it a several times and, therefore, mostly use a jig (Veritas MkII). Pull-lift-pull is not for me. But, as I don’t always dig into the stone, it looks like even someone as ham-handed as me could perfect that method on water stones with more practice. One slip is enough to cause some damage to the stone, though.

    Anyway, for me, the urge to freely do free-hand honing is one of the main reasons for considering diamond stones. Add to that the flattening chore and, to a lesser extent, the mess with soaking. (speaking to self, lest I forget 🙂




    Aha, so my fear about ruining the DMT DiaSharp plates when used for flattening is real.

    @selva honestly, their information is confusing. The DMT web page for Dia-Sharp gives information for the 8″ bench stone and says, “This size comes in seven DMT diamond grits, including Extra Extra Coarse (XX) for rapid stock removal and waterstone flattening…” On the other hand, when I asked them in email a few months ago, they said “We do not recommend the DiaSharp. This is for sharpening only. It is not manufactured to flatten” and went on to say “The DIAFLAT has a special process nickel/diamond coating DMT calls HardCoat. This was developed to hold up to the abuse from lapping stones; water, oil, Arkansas, ceramic, etc.” So, the web page makes it sound fine, but their email said the opposite. The email also had a “use and care” manual for the diaflat product, and it says, “Some DMT Diamond Sharpeners in the past have been used; i.e. DiaSharpTM, for flattening, however, they were designed for sharpening, not flattening, therefore, DMT® assumes no liability for sharpening stones worn out due to this method of use.” The problem is that the DiaFlat is claimed to be suitable for flattening many kinds of stones, but water stones are quite soft. I have the impression that many people are using the DiaSharp for flattening, so you’ll need to decide. DMT is saying, no, though. The DiaFlat plate is scary expensive, though.



    Thanks to all who helped here and commented on similar threads in the past, I finally got two DMT 8″x3″ DiaSharp stones from Lee Valley: Fine (600 mesh) and X-Fine (1200 mesh). Skipped the coarse stone for now to see how this goes. Also kept my water stone option alive by replacing the worn out 1000 with a new one — flattening those is still by emery/sand paper on glass for now, but the plan is to commit to the “flatten as you go” regimen as @etmo suggested.

    First impression is mixed: the edges came out good, nice to be not worry about digging into, and needs no flattening, yay! But these plates appear to stay at those stated grits only for like 30 minutes? After a short use, they have become much smoother, still cutting okay, though. I’ve seen this “break-in” to higher effective grits reported here and elsewhere, but this fast? Hopefully that’s no cause for concern. Though it feels like most of the diamonds are gone 🙁

    I tried to round the corners of a plane blade by tilting the edge off the plate and gradually dropping down as Paul demonstrated (i.e., hone the corners). But that has put some ugly scratches on the X-Fine plate where I tried it. A bit disheartening to see such scratches on a brand new plate — is it normal?

    By the way, it seems, those who say diamonds cut fast have never used water stones 🙂 The latter cut way faster than these DMT plates at least. Not a concern for me as this is good enough except when a blade needs some serious repair. Also the burr created by the 600 mesh was much beefier than I normally get. Had to repeatedly chase the burr to get rid of it. Probably that will change as the plates break-in?

    PS: DMT suggested a different model (“interrupted” diamonds) as the recommended option for chisels and plane blades but those 8″ ones are 50% more expensive than DiaSharp and narrower (2 5/8″). I couldn’t afford those and I vastly prefer the 3″ width anyway.

    @ed Thanks for the clarification on using DiaSharp plate for truing water stones. The guys at LV suggested a silicon carbide + resin truing stone (much cheaper at ~USD 20 to 35 — they have two options) but then one may need something to keep that one flat in the long run. DiaFlat is out of my budget.




    @selva what you’re describing is normal. The stones are super aggressive for a short while. I’d choose the DiaSharp over the interrupted any day. The DiaSharp won’t catch the corner of a narrow tool. You got the right ones and, you’re right, the extra width is somewhere between useful and needed, especially if you ever get a wide plane.

    It’s a good idea to let the abrasive do the work rather than using heavy pressure, especially when you are working a corner. “Working a corner” may be more a matter of some extra (gentle) pressure towards the corner rather than a big lift / tilt of the iron. I doubt you’ve spoiled the plate.

    You’re going to want something coarse, but you can use 220 grit paper or 120. The coarse is used to work down the heel of the bevel so that the bevel angle doesn’t get too steep.



    After a short use, they have become much smoother, still cutting okay, though. I’ve seen this “break-in” to higher effective grits reported here and elsewhere, but this fast?

    Never heard of it happening that fast, but just the fact that it does happen is why I left diamonds. For me, it was slow and insidious…first they sharpen your edges fairly quickly, not as fast as good water stones, but do-able. Then they’re a bit slower, well, OK. Then a bit slower, and some months later, you’re spending 10 minutes just trying to get a burr on the finest stone.

    The slow boil prevents the frog from jumping out of the pot, right? So that really ticked me off, knowing I’d wasted so much time over months and months, but because it was so gradual, I never realized how bad it had gotten until it was ridiculous.

    Anyways, flattening with float glass is probably fine, except for the cost of the sandpaper over time. Those 30 dollar truing stones – I have one, and it’s not flat. How precisely manufactured is it likely to be for 30 bucks? I would flatten with the silicon carbide truing stone, then pencil in some marks, and repeat. I’d then pencil in some marks again, start to flatten with my DMT plate, and sure enough, there was a hollow in the middle of the stone still remaining.

    So I don’t trust the truing stone’s flatness, which is the real issue. Float glass, in a water-stone-sized piece, is probably flat to within a few thousandths of an inch over all. I just don’t know how long the sandpaper would last, and that might add up, eventually you’d have saved money buying the DiaFlat…

    There’s also the carbide powder thing, but I don’t understand how that works, thus I don’t understand if it works, so I’ve avoided it. Seems to me you’d get some areas where the powder clumps up, and thus those areas would have hollows, no?



    @ed Thanks. Glad to know DiaSharp is the right one — I was not going to pay extra for the “interrupted” model.

    The scratches are not deep so I too don’t think it ruined the plates. Good to know I’ve to put less pressure and let the diamonds do the work. Paul appeared to be putting a lot of pressure in those videos and my hands are nowhere as strong as his — can’t even open a jar most of the time. But have to keep in mind to be gentler. And, Paul’s method for the corners looks way too advanced for my skills — I was trying to put a show for myself mimicking Paul!

    So, I do need the coarse one for maintaining the bevel/heel. Well, had not understood the real reason for starting with the coarse one. Have to move the 220 grit one from my wish list to “buy soon”…

    Thanks again.




    @etmo You are right, sandpaper cost does add up. But I don’t see myself buying DiaFlat. Probably the cheap truing stone and then keep it flat with occasional use of sand paper on glass may be what I settle into for water stones.

    As for diamonds, its early days for me. If these wear out fast as you describe, I’ve water stones to go back to.




    I agree with much of what @etmo says, but I think the issue is for the grinding work rather than the honing. In other words, yes the stones cut slower after some use, but if I have a shallow grind on the tool, say around 25 degrees, then I can get the tip very rapidly even on plates that are at least 5 years old. So, how to get to that starting point?

    I think this is why Paul says to spend so much time on the heel. If you start with a grind at 25-ish, you can take just a few passes at a little less than 30 and have just the tip sharpened. On the next sharpening, you work the heel for a minute or so, then lift a little and a few passes gives you a honed edge at 30 ish. Repeat again, you get a few minutes work on the heel, and a honed edge at a little over 30. After a few cycles, the edge is gettng too thick and you need to get back to your 25 grind all the way to the edge, but you’ve been investing time in the heel, so it isn’t so bad. To be clear, all of what I’m saying is Paul’s convex bevel. It’s like I have a convex bevel at 25 ish that goes to the heel and and then lift and have a convex bevel at the angle I want for work, but just at the very tip.

    So, here’s where the problem comes in. Of all the stones, the coarse or XX coarse are the ones people complain about the most for losing their power. Although paper is expensive, it is a way to get started for the coarse grit and see if you want 220 or 120. Since you are only using it for the bevel, it doesn’t matter what you put it on. Flatness isn’t very important.

    Confession time: I splashed out for the DiaFlat 120 grit plate. That’s how I get my heel down. Sometimes, I think about getting one of the super aggressive water stones because, for this purpose, it can look like a banana.

    Just so it is said: I do not think this method works on A2, just on O1 and, even then, I lose my patience on thick O1 like Clifton was using. A2 is just too hard for this. It can be done, but I don’t have the patience for it unless it is a small blade. @etmo Are you using super-hard Japanese steel and A2? That would change everything for me.

    Anyway, my suggestion is to play with paper for your lowest grit for some time until you establish your sharpening routine and know what you want. Keep in mind, though, no plate will be as fast as those first 50 strokes on paper.

    • This reply was modified 9 months, 3 weeks ago by  Ed.


    Good points @ed, and thanks for the tip about maintaining the heel down with something aggressive. Anyway, I’m going to try hard to make this work for me. If these plates last a few years for Paul, should serve me a life time. Going back to water stones is always an option but I’ll put that thought away for a while.

    Hope Paul doesn’t get wind of this thread and chide us for debating this “first-world”-ish problem..




    ed and I agree — grinding is the issue. As ed surmised, I’m using mostly cryogenically-hardened A2 and some japanese steels, so my grinding gets done on an actual grinder with a cbn wheel. Like ed, I just don’t have the patience to spend a long time grinding by hand.

    Good advice from him on finding your lowest grit. That’s where it all starts, and what takes most of the time. Imagine you get a vintage 1″ pigsticker off ebay, it’ll take you 30 minutes, easy, to flatten the back of that beast, and maybe much longer, depending on the condition. If you’ve got the time and the inclination, no worries. If it rankles, switch up your lowest grit. For me, no grit by hand was fast enough, hence the grinder.

    Same with the bevel. A big 1″ bevel takes a lot of sharpening. Changing that bevel angle takes way, way more time. Again, if you’re OK with the time is takes with your current media, you’re done, but otherwise, try a coarser grit until the juice is worth the squeeze. For me, I had to go to hollow grinds off my grinder. With a cbn wheel, I can grind right to the wire edge with no fear of burning the metal, usually in around 45 seconds? Here’s a video of the process, done by Joel at Tools for Working takes him less than 45 seconds:

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