The Diamond Plate Progression

In The Honing Progression entry, an example of apex geometry refinement during honing with Shapton glass stones was presented.  A slow, but linear improvement in sharpness and keenness was observed, consistent with the intuitive view that reducing abrasive size (increasing grit) leads to a sharper, keener and more linear edge, along with a more polished bevel.  In the current discussion, examples taken from honing on diamond plates will show that the reality can be more complex.

There are two primary differences between diamond plates and conventional water stones; the diamond plate grit is more firmly bonded, and can exert a greater lateral force without dislodging, and second, unlike a water stone, fresh grit particles are not being continuously exposed with use on the diamond plate surface.  It must be anticipated that the effect of a particular diamond hone will depend on the existing condition of the surface; whether the stone is broken-in, worn, glazed, etc.  For this reason, the examples here cannot be generalized to all diamond hones.

A set of 4 diamond plates were used for this experiment; DMT coarse (325), fine (600), extra-fine (1200) and extra-extra-fine (8000).  The four plates were in good condition, and were “broken-in,” all having been used for more than one hour polishing steel.  A carbon steel razor with spine-apex angle of 16.5 degrees (inclusive) was honed edge-leading with pressure in the range normally used for honing straight razors; beginning with a force-equivalent of a few hundred grams, reducing to near “weight of the blade” pressure at each stage.  The observed results were confirmed repeatable, indicating relative insensitivity to variations in pressure, stroke type and number.

Comparing side view images, all at 5000x magnification, shows that the roughness of the bevel actually increases with grit, rather than decreases as was observed with the Shapton water stones.  The scratches are wider and shallower on the lowest grit hones, becoming progressively deeper with increasing grit.

DMT325_p_05

5000x magnification side view after honing on the DMT 325.

DMT600_p_04

5000x magnification side view after honing on the DMT Fine (600).  Scratches are narrower but deeper than those in the DMT Coarse (325) honed bevel.

DMT_1200_45_02

5000x magnification side view after honing on the DMT Extra Fine (1200). Scratches are both wider and deeper than those from the coarser grit hones.

DMTEEF_p_04

5000x magnification side view after honing on the DMT Extra Extra Fine (8000). Scratches are narrower but deeper than those from the DMT Extra Fine (1200) honed bevel.

Imaging edge-on also shows the counter-intuitive result of decreasing edge keenness and uniformity with increasing grit.

DMT325_01

10000x magnification side view after honing on the DMT Coarse (325).

DMT600_x_04

10000x magnification edge view after honing on the DMT Fine (600).

DMT1200_E

5000x magnification side view after honing on the DMT Extra Fine (1200). Note that the magnification is reduced from the 325 and 600 grit images to better show the non-uniformity.

DMTEEF_x_02

3000x magnification edge view after honing on the DMT Extra Extra Fine (8000). Note that the magnification is further reduced from the preceding images to better show the relative irregularity of the apex.

The edges were also cross-sectioned and imaged to determine the near-apex bevel angle. 3 of the 4 edges display similar micro-convexity, with the 600DMT edge being a foil-edge burr.

DMT325_x_08

10000x magnification of the apex cross-section after honing on the DMT Coarse (325). Edge width is less than 100nm.

dmt600_2_04

10000x magnification of the apex cross-section after honing on the DMT Fine (600). Edge width is approximately of 100nm. The apex angle is approximately 14 degrees, measurably less than the spine-apex angle of 16.5 degrees – a foil edge by definition.

DMT1200_X_measured

10000x magnification of the apex cross-section after honing on the DMT Extra Fine (1200). Edge width is sub-100nm in places due to convexity of the last micron of the apex. The bevel angle 3 microns from the apex is 19 degrees, but is significantly larger nearer the apex.

DMT_EEF_04

10000x magnification of the apex cross-section after honing on the DMT Extra Extra Fine (8000). Edge width is not quantified due to the irregularity of the apex.

The reader could be forgiven for concluding that these results make no sense, that the author has no honing skill, that these particular plates were defective, that razors are completely different from knives, or any other dismissive explanation.  Often, results that contradict our intuitive expectations are a key to identifying and improving our deficient understanding.  Certainly it would not be prudent to generalize these results and a full understanding of these observations will require further experimentation; however, a few insightful comments can be made at this time.

In order to form a scratch, sufficient pressure must be exerted by the particle (or a corner of the particle) to exceed the yield-strength of the material.  Since pressure is inversely proportional to contact area, a larger smoother particle will require a greater force to scratch than a smaller or more irregular particle.   The observed scratch profiles indicate that the Coarse(325) and Fine(600) diamonds are too large (and smooth) to individually penetrate the steel (at the force applied), instead only the asperities on the surfaces of the diamonds abrade the bevel.  This is not a burnishing effect; metal is being removed in these examples.  The Extra Fine(1200) and Extra Extra Fine(8000) diamonds are small enough or sharp enough to penetrate and form discrete scratches.  The smaller surface area of those contact points results in a higher pressure (force/area) and therefore greater penetration and deeper scratches. In the pasted strop-part 3, it is shown that the transition from a triangular profile to micro-convexity can include the formation of a foil edge.  For this reason, the observed foil-burr in the 600 grit example is not inconsistent with the apex profiles observed after the other three grits.

It is surprising to observe micro-convexity on an blade honed on an incompressible, flat surface (without slurry).  Further, the amount of micro-convexity does not vary with grit size; we observe nearly the same near-apex profile after the 325 as we do at the higher grits.  One possible explanation can be found in the fact that plastic deformation occurs at the apex during honing.  The amount of plastic deformation is a function of the steel and bevel angle, not of the of the grit size on the honing substrate.  A likely mechanism for this result is shown schematically in the images that follow.

deflectted

The apex is deformed away from the hone by a glancing collision with a diamond particle.

sheared

The metal is pushed beyond the bevel plane and is abraded during the return stroke.

microconvex

With abrasion of the deflected apex becomes micro-convex.

When the bevel is convex, the apex rides above the surface and is somewhat “protected” from direct collision with abrasive.  This can enable the production of an edge much keener than might be anticipated for a particular grit size.

Almost any measure of sharpness or keenness of these four blades would show a reduction in cutting efficiency with refinement on higher grit plates.  The expectation that low grit edges are “toothier” may lead someone to believe that a toothy edge is superior in some applications.  However, the micrographs show no evidence of “toothyness” in the 325 or 600 grit edges.  In fact, those edges appear highly refined.  Whether the 1200 and 8000 grit edges could be qualified as “toothy” is up for discussion.  Certainly the toothy-blade myth is something to be investigated further.

The 325 DMT finished edge (shown below) has the characteristics of an ideal straight razor shaving edge.  Three different straight razors were honed on this DMT plate and confirmed to provide an excellent straight razor shave, as would be expected from the highly refined apex profile.  A remarkable result, but unlikely to start a trend among straight razor users to finish their honing with a DMT 325 plate…

DMT325_06

30kX magnification cross-section view of the apex following honing on the DMT 325.

 

For comparison, a blade was honed on an Atoma 400 diamond plate.  This plate was used exclusively for lapping waterstones, resulting in a rougher, less polished surface.  Images of the blade display a scratch pattern consistent with that irregular surface; the scratches are much narrower than the size of the diamond particles.

atoma400_e_01

Edge view image at 10kX magnification of a blade honed on an Atoma 400 hone.

atoma400_p_02

Side view image at 5kX magnification of a blade honed on an Atoma 400 hone.

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36 responses to “The Diamond Plate Progression

  1. I am very surprised by the results you show – I would have expected exactly the opposite. As you said, the scratch patterns are undoubtedly a result of the size of the diamond particles and their roughness/smoothness, and also the uniformity of the surface of the diamond plate. I am surprised too by the difference between the Atoma 400 plate and the DMT 600 as I would have expected similar results from those two plates. Why would the diamonds be any different whether the plate was used for lapping waterstones or sharpening steel?

    I don’t suppose you have micrographs comparing the surfaces of the 5 diamond plates you used?

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    • Intuitively, lapping waterstones of various grits should leave a rougher surface on the diamonds than simply abrading steel. It would be possible to systematically study these effects, including taking micrographs of the diamond surface. However, without an industrial sponsor, it is unlikely I will investigate this in the foreseeable future.

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  2. Awesome write-ups Todd. Your Atoma 400 must be way less worn than mine; at your instigation (don’t know if you recall our talking about it at BF) I shaved from both my Atoma 400 and my DMT 325. Both shaved very well, to include ATG. Keep up the good work, your blog makes for great reading!

    –Eric

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    • Thank-you Eric. None of the plates I have used are particularly worn.
      I believe you are the only other person to try the DMT 325 shave challenge.
      It is telling that some people will shave from a razor honed on a rock they found in their garden, but will not try shaving from DMT 325 given the evidence shown here.

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  3. It would be quite a nice thing to see the difference at high magnification between a worn-in diamond plate and a fresher one also! I can’t say how many times I have had guys argue with me about wear on the plates and say things like “diamond is so hard it doesn’t wear.” Clueless!

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  4. In regards to the “tooth” or general use of that term, it refers to the uneven height of the apex (distance from the spine) not the with of the apex. In the above pictures it is fairly large, on order of ~5 microns which would yield a large saw/like effect in draw/slice cuts.

    Note that the DMT’s when new, in the finer grades are really susceptible to clustering of the abrasive. This is so strong that in many of them they can clump so high that if they are not ground off they force edge trailing passes.

    A new MXT DMT rated at 6-microns will readily produce scratches far deeper than a new fine (25 micron) just as you have seen. This is why most people recommend lapping the x-fine and above diamond plates initially, or at least taking care with lubricant / trailing passes until they even out. Otherwise they can end up just lowering the edge finish exactly as you have seen.

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    • The plates I have used are definitely much smoother than when new. How the results would vary over the life of the plates will have to remain an open question. This is one of the reasons that this demonstration should not be generalized.

      This particular 8k plate was essentially unusable until worked with a screwdriver shank for about 30 minutes. I have made a serious effort to smooth this plate; there are a significant number of scratches with no diamonds remaining (under an optical microscope, it appears that approximately half the surface has no diamonds remaining). I am skeptical that particular plate could ever perform as a high grit hone.

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  5. On page 22 of John D. Verhoeven’s pdf at

    http://www.bushcraftuk.com/downloads/pdf/knifeshexps.pdf

    the following quote relates to your interesting observation of deeper/finer scratches at putatively finer grits. Your observations and hypotheses extend/expand his casual mention,of course. Love your site.

    “Interestingly, careful comparison of the edge quality of the blades done with the 2 stones indicated that the abrasive grooves were perhaps slightly finer on the supposedly coarser 6000 grit stone. The results indicate that an advertised finer grit in this 6000 to 8000 size range does not guarantee a finer abrasive action.”

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  6. “Since pressure is inversely proportional to contact area, a larger smoother particle will require a greater force to scratch than a smaller or more irregular particle.”

    So after reading this I would be curious to see what would happen if you use more force on the lower grits, thereby causing the larger particles to actually penetrate the steel, and much lighter force on the higher grits. Very interesting also your results and the difference between the Atoma and the DMT. I would like to see something done w/ the Wicked Edge diamond plates as well if you have time as I find my best edges off of the 1k diamond stones vs. the 400 stones. 1k seems to be much keener.

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    • Josh,
      I experimented with increased pressure on my 325 plate and this resulted in micro-chips at the edge. However, between the chips, the edge was unaffected (still very keen). It may be that those chips were caused by a single asperity on the plate. I also found that using lubricant (Norton oil) allowed me to hone a razor without chipping (viewed with a 10x loupe).

      Again, I would not generalize these results. My primary goal in presenting these images was to show that grit size is not the only factor.

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  7. I’m shocked. It seems to me that the world is moving in a “reverse way”. This is the most counterintuitive thing I’ve ever heard in my life. If I had a DMT 400 I would try it for sure! However, if your hypotheses were verified, tons of theories and religious beliefs that have accumulated over the years around the concept of “smooth shave” should be destroyed in a moment (and people tend to become attached to their own beliefs). Great article.

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  8. Very nice article. Very clear and concise style – I appreciate that.

    I have an “AccuSharp Diamond Pocket Stone (027)” purchased from the hardware store.
    http://accusharp.com/products/027/index.html

    One side is 350-grit and the other is 800-grit. I do not recognize the “grit” unit of measure, but assume if nothing else it provides a relative indication of abrasive particle size. At first use I deemed it almost useless for knife sharpening because it was so course on both sides.

    I used it on a couple of axes for a while in place of a file, and now I can’t tell by touch which side is the 350 and which is the 800, but one side is noticeably more abrasive than the other – you can only tell by the increased friction on the steel when sharpening. I thought that was interesting, but gave it no more thought until I read your blog.

    Forgive me if I lack the language to convey my thoughts.

    This article makes me thing your results ought to have been obvious – we have no idea the shape of the particles but are fairly certain that diamonds won’t be worn flat by hardened steel, though any protrusions might be broken off. Any diamond particle with a shape not sufficiently supported, i.e. too sharp, will probably fracture into a less aggressive exposed surface when abraded. It really stands to reason that the smaller particles will have more support from the adhesive than the larger particles, and being smaller will offer more friction-inducing contact per square inch. Hell, the smaller particles are probably the size of what’s knocked off the larger grit elements. I imagine the fine surface as a board covered with the sharp end of tacks clustered as close as possible, while the “course” surface (after breaking in) I see as rounded beach or river gravel the size of your thumb comparatively. Course is tough enough to abrade steel but not sharp enough to gouge it, while the fine is still sharp and easily capable of carving long grooves into any surface dragged along it. I hope my lack of vocabulary doesn’t detract from what I’m saying.

    That said, I’m thinking there is a simple way to see the relative diamond grit sizes and their effect. You have made me think that I might be able to press and/or drag each side into exposed and developed film to create a path for light based on the amount of material punctured or removed. Once can then project the image created to easily magnify and examine the resulting effect. I would assume film would respond to abrasion or impression similar enough to steel to make such analysis relevant. A substrate of consistent density throughout would allow a person to determine the depth of the scratches by brightness levels in photoshop after scanning. If the opaque layer was confined to the surface, one could still determine the relative size of the particles.

    I’m going to give it a try, inspired by your work.

    Like

  9. I don’t understand the comment: “The expectation that low grit edges are “toothier” may lead someone to believe that a toothy edge is superior in some applications.”

    Liked by 1 person

    • I plant to write an article or two on “toothy” vs “polished” in the future that will better explain these concepts.

      Commonly, there is an assumption of a linear relationship between grit size and apex refinement. Very simplified, that coarse grits produce “toothy” edges and fine grits produce “polished” edges. While this does occur in some situations, it is not generally true. In the example here, we see (only visible at these very high magnifications) the inverse relationship.

      My point, in that comment, is that these particular low grit edges (325 & 600) feel sharper and perform better than the high grit (1200 and 8000) blades. In this case, it is because they actually are sharper & keener, not be cause of “toothyness.”

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  10. This is a wonderful site. You’ve answered some of my greatest sharpening questions and turned my understanding of the subject upside down. After sharpening a higonokami on my cheap Harbor Freight diamond block’s #300 grit side this morning and shaving the back of my hand, I believe your microconvexity theory.
    If more compressible surfaces -coarse sandstone and the like- exhibited the microconvexity effect this might go to explaining the ability of Western, Middle Eastern, and African carpenters of yore to plane, pare and cut very difficult woods prior to the invention of the Shapton 8k. If Moxon’s recommended sharpening method was standard Elizabethan practice -grind stone then whetstone- apparently that was enough to carve ebony into furniture. Modern mokonde sculptors carve wet Blackwood with even less.
    If this works for woodworking tools -and why wouldn’t it?- I can’t justify walking my way through 5 different grits. If it takes ~30 seconds max to refresh a chisel edge on a diamond block, why bother?
    Thanks again. Keep it up!

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  11. I would conclude that on the higher grit diamond plates, the density of the diamond is too low. By way of example

    On a fine diamond stone, the density of the diamonds would have to increase at the same rate that the diamonds get smaller. If a coarse stone has diamonds of size x, then if there is a finer stone with diamonds of size x/2, then the same number of diamonds on the plate would give you 1/2 the density per area assuming an even distrbution.

    I’m sure there are more diamonds on the finer stone than the coarse, but are three enough to make up for the loss in size of the diamonds. I speculate there is not.

    The rough diamond stone would act like a fine tooth come if you rub your hand accroos it, there are so many teeth that the pressure is distributed such that each tooth only bears a small amount of pressure. Now take 1/2 of the teeth away, the same pressure exerted by your hand is borne on a smaller amount of teeth. Do that with something as hard as diamond and it’s going to cut in further to the steel. It could poteentially cut in as deep as the diamond is above the nickel or whatever it’s bound to. If the fine diamonds don’t make up in density what the fine diamonds give up in size compared to the coarse diamonds, it follows that they woudl scratch deeper and in a more sparse pattern.

    Perhaps with current diamond plating technology, there is a limit to the density that can be achieved. Perhaps its a current technology or process limitation, or perhaps driven by price point, not sure. It would be nice for a current manufacturer to “come clean” so to speak, but I think non of them want to because it might accentuate the point that at the finer grits, above 1200 in diamond stone grit terms, you are better off with an Arkansas, Waterstone, Coticule, Ceramic, or Waterstone than with diamond, which some folks have concluded or decided on their own already. If they handn’t why woudl they be flattening watersones with diamond stones rather than just using the diamond stones.

    I’ve done no tests, but this is a hypothesis based on what I’ve read here and elsewhere about fine diamond leaving scratches much deeper than expected.

    Like

    • There is a very important concept that is almost universally misunderstood and that is that the depth of scratches produced by a flat hone is much shallower than the size of the abrasive. A deep scratch is formed when one ( or a very a small number) of abrasive particles sits higher than the average surface. In this case, the pressure is enormous since the force is applied over the contact area of a single grit particle.

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      • Todd, I’m too ignorant to know if you are agreeing with me, disagreeing or merely pointing out a fact I may have missed.

        I will say though it seems as if we could manufacture diamonds to a particular shape and embed them sufficiently closely the higher grits would not scratch as deeply as they do.

        Your results indicate, at least as far as DMT hones and this one test are concerned to stop at a lower grit and finish with a different material than diamonds.

        I have a Trend 1000 grit credit card, a DMT 1200 grit credit card and an Eze Lap 1200 grit bench stone. The DMT and Trend are about equally broken in and the Eze Lap is a bit newer. The DMT leaves the worst finish of the three and the Trend the best. I’ve heard the Eze lap will break in nicely. Not there yet.

        I also have an Atoma 400 that has only flattened one water stone once well over 6 months ago. It serves only as a sharpener now. It leaves a nice uniform pattern. I wonder if it would fair better under your microscope.

        Lately I’ve been experimenting with the Fallkniven DC521. 600 grit diamond on one side and ceramic on the other. I like it. I can strop after the ceramic side and have a nice usable edge for my wood carving. It’s a good traveling kit. One bench stone a slip stone and a strop is all I need to be functional.

        Of course wood carving tools are another thing completely as I sharpen them with the direction of sharpening parallel tot the cutting edge rather than perpendicular as chisels and plane blades are commonly done. To be clear I do strop perpendicular to the edge.

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  12. So far I have used the concepts presented here in restoration then use of about 10 old razors. After using the DMT 325 to repair the edge, straighten the spine if necessary and then set the bevel, in every case I went directly to a ‘finisher’, be it Nani12k, Coti, Chinese or purple Welch slate. This with Solingen, Swedish and Sheffield steel. The results in every case have been excellent and consistent with shaves as good or better than any I’ve had. Just wanted to report back and say thanks.

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  13. Todd, I just noticed a caption error above – you have two apex detail shots in a row captioned as the DMT325 when I think the 2nd should be the DMT600. BTW, I went ahead and shaved with a DMT325 edge again for the recent discussion at the other site – I posted some images from my scope there also. Another nice shave. It appears that the convexing on my razor is taking place in the last 6-8 microns of the bevel. I wonder if this is a variable depending on the dullness or wear on the surface of the diamond particles.

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  14. Hi again. I hope it’s ok, I used some of your images to help someone new to honing regarding his DMT extra extra fine. The forum rules don’t allow me to post links to other websites, although I wish I could.

    Also, when are your next findings going to be published? Any hints on what it touches on?

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  15. Hi Todd,

    Out of great curiosity I have to inquire. Would a similar grit aluminum oxide (fine Norton India) stone give comparable results? Reason I ask is the India is around 9 on the mohs scale and just under diamond in hardness. Similarly being an oil stone it is not in it’s nature to shed any grit or once broken in at least.

    What do you think?

    Like

    • I haven’t looked at the various coarse sintered stones in any detail. Certainly they can become “glazed” and produce much finer results than expected as the diamond plates do.

      This type of stone is typically quite porous and loose grit can be come lodged in the pores and not flush away easily. The ‘open’ structure of the diamond plate surface will allow loose/broken grit to be flushed away more easily.

      Both types of hones will shed or have grit broken (the do wear, albeit slowly),and it only takes a small number of these particles to lodge in the surface sitting higher than the surrounding (fixed) grit particles to produce a large effect.

      Like

  16. Since the edge looks great after the DMT coarse, I wonder how the improvement would look like with additional denim and diamond on leather with your equipment. Particularly for knife sharpening, finishing edge leading on DMT coarse, then only denim and leather after depending on how much finish you want. Any thoughts? I’d love to see pictures with that finish.

    Like

  17. Excellent work. A systematic approach to understanding the ‘arts’ often challenges deep-held beliefs. Treading on this ‘sacred ground’ can be expected to stir some controversy — the price of progress.

    Philosophy aside, I have two pragmatic questions to check my understanding of some of your results.

    Question #1: Am I correct here that a single honing on the 325 grit diamond plate produced a result, at least in terms of edge width, that is similar, or perhaps even keener, than achieved by honing on the 1000 grit Chosera followed by the 2k, 4k, 8k, and 16k Shaptons?

    From ‘The Honing Progression’ writeup: “The convexity near the apex is removed by the 4k level, and the measured geometry is unchanged with higher grits beyond the 4k. Beyond the 4k level, the bevel polish is refined and the edge width is reduced from about 0.3 microns to about 0.1 microns.:”

    From this ‘Diamond Plate Progression Writeup’: 10000x magnification of the apex cross-section after honing on the DMT Coarse (325). Edge width is less than 100nm.

    Question #2: If the above result was deduced correctly, would it be reasonable to also conclude that the the equally, or perhaps more, keen edge of the blade sharpened using the 325 grit DMT stone would also be more robust sue to its more convex (i.e. less ‘sharp;) geometry near the edge?

    And, lastly, what kind of generalizations and/or cautions would you dare offer with respect extrapolating results from your controlled ‘straight razor’ experiments to the more complex world of different blades (i.e. steels, geometries, etc. )

    Like

    • You are correct, the blade finished on my 325 grit diamond plate was keener (and shaved better) than one finished on a progression ending with the 16k Shapton.
      Again, I don’t want to generalize this result. I have only one 325 grit diamond plate, but I was able to consistently repeat this result on several blades. I have recently been using that plate for plane blades and chisels, and at some point I will check to see if this “reconditioning” changes the results for straight razors.

      My experience has been that micro-convexity improves the longevity of the blade for shaving or light tasks like cutting paper.

      Although the diamond plate produces a micro-convex apex with very similar geometry to one produced by stropping, the apex will experience much greater deformation when honed on the diamond plate than it will on the hanging strop. I haven’t studied the mechanisms of dulling systematically enough yet to speculate about which would be preferred for particular applications.

      The primary difference between straight razors and other blades is the small bevel angle. Below 20 degrees (inclusive) the steel is flexible and easily damaged. I haven’t systematically studied higher angles, but up to about 30 degrees the sharpening effects are similar to those observed with straight razors. With other blades, keenness (or push-cutting ability) is not necessarily the goal.

      Like

  18. Hi Todd. Thanks for the excellent and counter-intuitive post. It seems like the higher grit diamond plates are removing more material for each stroke. If you had to use one of your DMT diamond plates tested here to change the bevel angle on a chisel or a plane iron by a few degrees, would you prefer the higher grit plate 8000 XXF to set the bevel, and then finish off with a coarse 325, or would you simply use the 325 all the way through?

    I’m a wood worker, but not a razor shaver. You’ve changed the way I sharpen my tools. Thanks for all your work.

    Like

    • I’m cautious about generalizing since I’ve only tested the single 8k EEF plate that I own; however, the majority of other’s comments I’ve read suggest that mine is typical. I’ve also only tested the three 1200 EF plates that I own, but the consistency of these three suggests they are also typical. Keeping that in mind…

      (The abrasion rate vs grit post is also relevant to this question).

      I have absolutely no use for the 8k EEF – it removes metal at the same rate as the 1200 EF, but leaves substantially more damage.
      (I’ve spent hours trying to break it in).

      The coarser DMT plates require more pressure to cut than I can achieve when sharpening a chisel or plane blade (I use a Veritas MK II jig, which limits how hard I can “lean in” and maintains the contact angle so there is no pressure increase due to convexity. So again, I have no use for the 600 F and below.

      To answer your question, the DMT 1200 EF is the only hone I use for my chisels and plane blades. It’s as fast as any hone I own (in that pressure range) and it leaves relatively little damage to the apex.

      Typically, I’ll follow with a 1k Chosera or 2k Shapton waterstone (whatever is handy) with edge trailing strokes and then strop on the denim with metal polish, and finish with diamond on leather).

      Like

      • Thanks for sharing your process. I’ve been using my 8000 grit DMT for major plane iron and chisel surgery since I read the abrasion rate vs grit post. I have that in a wider format than my 1200 grit DMT, so I’ll probably stick with it for the moment just because of the ease of use, but I’m glad to know what you find useful for honing your tools.

        Clearly you have a technical background, so this may be a completely useless offer but: if you’d like to run some statistical analyses on this stuff to include in your blog, I’d be happy to donate some time as a thank you for the value you’ve added to my hobby.

        Like

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