Recommendation? DMT stones: continuous vs interrupted surface

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maximus83

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For those who have used both the DMT continuous surface and interrupted surface diamond bench stones: Which do you prefer, and why?

Background: I do NOT want to start a religious flame war on this stone is "better" than that stone. Just want to know which style you personally prefer, and what led you to that perspective after using both. I have DMT interrupted myself for I think it's been about 5 years, and like the results they get, really awesome. But struggling with the "bumpy" feedback you get while sharpening along with the fairly frequent tendency to catch knife points in the plate holes. That non-smooth feedback from the stone is so distracting, I'm wondering whether switching to continuous would give a better sharpening experience and equally good or better results.
 
maximus83 said:
For those who have used both the DMT continuous surface and interrupted surface diamond bench stones: Which do you prefer, and why?

Background: I do NOT want to start a religious flame war on this stone is "better" than that stone. Just want to know which style you personally prefer, and what led you to that perspective after using both. I have DMT interrupted myself for I think it's been about 5 years, and like the results they get, really awesome. But struggling with the "bumpy" feedback you get while sharpening along with the fairly frequent tendency to catch knife points in the plate holes. That non-smooth feedback from the stone is so distracting, I'm wondering whether switching to continuous would give a better sharpening experience and equally good or better results.
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I've said it before... if you're catching knife tips in the hole of the interrupted surface, chances are, you're ever so slightly grinding that tip off on a continuous surface. That's a technique issue.

I've used both... I actually find the interrupted stones to have a better feel than the continuous. Feels more like (although obviously not the same as) a "regular" stone. I've never noticed it feeling "bumpy", (and not sure why, since the holes are lower).

That's my experience... both are great stones though, so I'm sure you'd get use out of a continuous stone, if you got one and just tried it for yourself. (Most of the answer depends on how you sharpen, and what you're used to, anyway).
 
cbwx34 said:
I've used both... I actually find the interrupted stones to have a better feel than the continuous. Feels more like (although obviously not the same as) a "regular" stone.
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What was your experience with the continuous stones? I've never had a chance to try one.

ETA: Also another issue I've had, which could be my technique, but it seems like the way the interrupted stones are designed, you don't get full sharpening right up to the very edge. I've had numerous occasions where I've been trying to profile a blade that maybe didn't have a sharpening notch or much space between blade and handle. When I tried to sharpen the heel on such knives right on the very edge of the stone, I could not get very good results at that point. Again I'm wondering if that interrupted surface could be the cause.
 
cbwx34 said:
I've said it before... if you're catching knife tips in the hole of the interrupted surface, chances are, you're ever so slightly grinding that tip off on a continuous surface. That's a technique issue.

I've used both... I actually find the interrupted stones to have a better feel than the continuous. Feels more like (although obviously not the same as) a "regular" stone. I've never noticed it feeling "bumpy", (and not sure why, since the holes are lower).

That's my experience... both are great stones though, so I'm sure you'd get use out of a continuous stone, if you got one and just tried it for yourself. (Most of the answer depends on how you sharpen, and what you're used to, anyway).
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^This is more or less my take on the comparisons between the two.

I have & use both. As mentioned above, technique accounts for about 99% of difficulties with tips catching. Always keeping the tip trailing (following the rest of the edge) to the very end of the stroke eliminates virtually any chance of catching. The tip should come off the hone pointed at least somewhat to the rearward end of the stone. Also, if the heel of the blade is lifted too high, too soon, in finishing the stroke, the tip may be momentarily angled down into the 'holes' on the hone, which could also be part of the issue.

Feedback-wise, the continuous hones can spoil you for them, as they can feel buttery-smooth at times. That being said, the 'bumpiness' felt on the interrupted surface can be an indication of pressure being a little heavy, or the approach angle being a bit too high (bevel not flush, with shoulder lifting away; therefore the belly 'dips' down into the holes), or some combination of both factors. If the bevel is flush and the pressure is suitably light, the edge should just literally skim over the open holes on the interrupted surface, as if they're not there at all. If you notice any 'wavy' appearance to the bevels as well, that could indicate pressure's too heavy on the interrupted surface.

The large Duo-Sharp hones (interrupted surface) are also guaranteed to be very flat, by DMT. That helps if you're grinding chisels, plane irons or other dead-straight-edged woodworking tools that need to stay as such. I also think, in the larger bench hones, you get a little more bang for the buck in the large, dual-sided Duo-Sharp hones. I tend to favor them for bigger grinding jobs (thinning/reprofiling), after which the lighter finishing work is a breeze on smaller hones.

Edited to add:
BTW, I have three Harbor Freight diamond hones, on which the oval 'holes' in them are colossal and deep, as compared to DMT's hones. I don't have any issues with tips catching on those ones either, for the reasons mentioned above.


David
 
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^Thanks David. Have you experienced the issue I mentioned with SOME knives, where there's not a sharpening notch at the heel or much space between heel and handle, and then when you have to sharpen right up to the edge of the stone, you have problems? I'm not sure what's going on there, if it's me or the stone, but I've run into this issue about 3x in the last month alone when trying to use DMT. In the end, with those 3 knives, I had to jump over to the Baryonyx stones I have to be able to easily sharpen right up to the edge and get those knives sharp at the heel.
 
Geometrically there shouldn't be any difference between DMT and Baryonix if both are flat in regards to sharpening up to the base where there is no sharpening choil.

My guess is that on Baryonix you're able to exert more pressure to grind off the raised area (see this video
to understand why I like sharpening choil), while on DMT with light pressure it'll take longer. Sorry to be blunt but it's the technique rather than the stone for this case.

I only have DMT Diafold EEF (holes) and DMT Credit Cards EEF (continuous) to compare. I like the card better for it allowing my technique to be more sloppy. Actually if not sloppy, there shouldn't be any difference, IMO.
 
Chris "Anagarika" said:
I like the card better for it allowing my technique to be more sloppy. Actually if not sloppy, there shouldn't be any difference, IMO.
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Slightly tangent to my thread subject :-), but who cares, still interested in this. Can you elaborate details on why you like the card better than the folding? I have both and found the folding C/F one worked very well for backpacking. The credit card one I have is F and for me, just not as easy to hold onto and sharpen safely at the same time.
 
I hold them the same: ends between thumb & middle finger, index knuckle supporting from below. The folding handle is spread to give room for middle finger.

Be careful when sharpening fast, one of the stroke can end into the finger holding the stone. I got cut once when being reckless & tried to hurry up the process. ;)
 
maximus83 said:
^Thanks David. Have you experienced the issue I mentioned with SOME knives, where there's not a sharpening notch at the heel or much space between heel and handle, and then when you have to sharpen right up to the edge of the stone, you have problems? I'm not sure what's going on there, if it's me or the stone, but I've run into this issue about 3x in the last month alone when trying to use DMT. In the end, with those 3 knives, I had to jump over to the Baryonyx stones I have to be able to easily sharpen right up to the edge and get those knives sharp at the heel.
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Part of that issue might be due to the fact that on a diamond plate (either continuous or interrupted), the abrasive only extends out as far as the edge of the plate's surface, at best, and not over/around the edge of the stone, as with an oilstone or a waterstone. And with some diamond hones, even DMT's at times, the abrasive coverage near the edge is sometimes a bit thin or sparse. So, a combination of limited exposure time for the blade's edge at the stone's edge, and possibly sparse coverage of abrasive at the edge, makes for a lot less grinding done per pass.

In general, the area near the heel doesn't get much of a chance, because it immediately sweeps away from the edge of any stone at the very beginning of the pass during a typical heel-to-tip stroke on the stone. It gets only a second or even a fraction of a second's worth of exposure to the abrasive on each stroke. That is, UNLESS one makes a concerted effort to keep the heel snug to the stone's edge, all the way along the length of the stone. It always takes longer to grind the heel very much, relative to the rest of the blade's edge, on any flat-surfaced stone.


David
 
Have folks using them found that the interrupted stones actually deliver on their stated reason for existence: they handle the swarf better, thus reducing loading, thus reducing messing with the stone while sharpening? Is there a significant difference in loading during sharpening between these and the continuous surface ones?
 
maximus83 said:
Have folks using them found that the interrupted stones actually deliver on their stated reason for existence: they handle the swarf better, thus reducing loading, thus reducing messing with the stone while sharpening? Is there a significant difference in loading during sharpening between these and the continuous surface ones?
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In my uses, I've never been able to tell the difference, in terms of the (claimed) attributes for the holes collecting more swarf. In fact, some time back, while I was using one of my Dia-Fold hones (interrupted), I wiped the hone with an old t-shirt moistened with some Windex, and noticed that almost all of the black, dirty stuff was coming from the abrasive surface and NOT from the recesses (holes) in the plate. I could see this, because the hone left a perfect pattern of it's (dirty) interrupted surface on the white t-shirt, after I wiped it, with the pattern of 'holes' coming off almost totally clean and white on the t-shirt.

In some uses, such as if one is doing a LOT of heavy grinding with a wetted/oiled interrupted surface hone, I could see that enough wet/oily swarf might eventually puddle up and flow into the recesses on the hone, thereby collecting some of it there. But in most of my light or moderately heavy use of them, I've yet to see much swarf collect in the holes themselves, as compared to what wipes off of the diamond surface itself, when I clean the hones. And that even includes reprofiling jobs. I'd think one would have to neglect wiping down or cleaning the hone for a long while, before seeing much stuff accumulate in the 'holes' on the hone.


David
 
Obsessed with Edges said:
In my uses, I've never been able to tell the difference, in terms of the (claimed) attributes for the holes collecting more swarf. In fact, some time back, while I was using one of my Dia-Fold hones (interrupted), I wiped the hone with an old t-shirt moistened with some Windex, and noticed that almost all of the black, dirty stuff was coming from the abrasive surface and NOT from the recesses (holes) in the plate. I could see this, because the hone left a perfect pattern of it's (dirty) interrupted surface on the white t-shirt, after I wiped it, with the pattern of 'holes' coming off almost totally clean and white on the t-shirt.

In some uses, such as if one is doing a LOT of heavy grinding with a wetted/oiled interrupted surface hone, I could see that enough wet/oily swarf might eventually puddle up and flow into the recesses on the hone, thereby collecting some of it there. But in most of my light or moderately heavy use of them, I've yet to see much swarf collect in the holes themselves, as compared to what wipes off of the diamond surface itself, when I clean the hones. And that even includes reprofiling jobs. I'd think one would have to neglect wiping down or cleaning the hone for a long while, before seeing much stuff accumulate in the 'holes' on the hone.


David
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Great, this is what I wanted to know. So really, it makes you wonder what is even the purpose, or the significant advantage (if there even is one), of getting the interrupted surface stones? I mean if the continuous give you smooth feedback, and don't really do any worse at loading, I wonder why the interrupted even exist.
 
maximus83 said:
Great, this is what I wanted to know. So really, it makes you wonder what is even the purpose, or the significant advantage (if there even is one), of getting the interrupted surface stones? I mean if the continuous give you smooth feedback, and don't really do any worse at loading, I wonder why the interrupted even exist.
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Likely the most obvious advantage to the interrupted-surface hones is weight. They're a lot lighter than the steel plate versions, making portability more relevant and attractive. The larger Dia-Sharps (continuous surface) are 1/4" thick steel, and very heavy for their size.

There might be some economic advantage in the manufacturing of the interrupted hones, but I don't know. Might also be simpler to control flatness in manufacturing as well, as the interrupted hones are guaranteed for it, whereas the continuous hones aren't. Solid steel plates are difficult to make perfectly flat, without expensive milling/machining of their surfaces.

And, as I mentioned before, in heavier wet grinding, the usefulness of the holes might be more apparent. I used a Dia-Fold hone a few years ago to lap/flatten a small ceramic hone, keeping everything immersed in water. Under that circumstance, the ceramic swarf tended to collect a little more in the holes on that hone, keeping the abrasive field clear and cutting consistently. But, on typical knife-sharpening duties, with a light coat of oil or water, I haven't noticed that same tendency much at all.


David
 
My guess is that the primary purpose of the interrupted surface is cost. It drastically reduces the amount of surface area loaded with diamond, therefore less cost in material while still giving you an effective area on which to sharpen. The reasoning of swarf collection is almost certainly marketing spin.
 
42, I think you're right. Marketing. The interrupted surface offers 50% less diamond product. Is it half price of the continuous surface stone? If not then it's marketing. DM
 
I took the number and size of the holes and added them together. Then subtracted them from the size of the entire plate.
That figure is very close to half the surface of the stone. How come you don't find this configuration on any other stone brand?
Only on the DMT plate? No other diamond brands do it. I'll grant it makes for a lighter product. But the less amount of product is there as well. DM
 
David,

Thanks. So half it is.

I have Taedea 360/600 folding sharpener with 'holes' as well.
Except that the 'holes' are not exactly 'holes' but 'bald spots' on the metal surface. Won't catch tips but the plastic casing around the plate hinders sharpening to the heel.
 
Smith's does interrupted surface as well, as do a number of other companies. It's a fairly common practice.
 
Other manufacturers use variations on the interrupted surface. Trend uses channels cut in a diamond pattern across some of their hones, and Atoma clusters the diamond abrasive itself in 'dots' arranged in a uniform pattern on their hones. In Atoma's case, anyway, they specifically mention the interrupted surface reduces the tendency for tools to stick or suction to the surface when lapping/grinding on a wetted surface. I could actually believe that, to some degree, and I think I've noticed a difference in that regard on DMT's hones, when comparing their continuous surface hones (which I usually use with some oil) to the interrupted surface hones. Maybe less of a tendency to 'skate' across the hone on a film of oil/water as well, for the same reason.


David
 
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