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Thread: My diamond stone experience

  1. #1

    My diamond stone experience

    As I spend more time using hand tools, I am visiting the topic of sharpening more and more. So for my last experience, I am asking the advise of the sharpening Gods (you guys) on this one. My past method of sharpening my bench chisels and plane irons is via belt sander, the Tage Frid method. However, the more I read and view on the topic, plus the urge to buy one more tool, led me to try out the diamond stones. My intent is to get to "scary sharp' in the least amount of time. My bench chisels currently are sharp, have mirror surface, but not scary sharp. So I set up my test by sharpening 3 chisels. 2 crappy Stanley chisels and one good Japanese chisel. I set up my 3 DMT stones and honed the edge using a Veritas honing guide. I lapped the edge on the 325 grit, 1200 grit, then the 8000 grit. I then stroked the chisel on a piece of leather with the red compound on it. My results were sharp chisels but NOT scary sharp. I passed the paper test, edge grain test, but had trouble with the shaving test. Although each chisel cut arm hair, they did not leave a clean swipe, which is what I was after. Also, after all that honing thru the grits, I can still see scratch marks on my bevel edge and back.
    So, my questions to you guys is:
    1. Why am I not getting to the scary sharp stage?
    2. Am I expecting more than these diamond stones can deliver?
    3. Is there a possible problem with my DMT diamond stones? They are brand new.
    4. Did I not spend enough time on the stones? I spent about 3 to 5 minutes at each grit.
    Thank-you for your insights and helping me to become a sharpening God like you. (LOL)
    John

  2. #2
    You first need a better indicator of adequate effort on each stone than the clock. You're looking for the result, not how long it takes. (With brand new stones and first time sharpening with the new system on the chisels, it's likely to be a bit longer than maintenance will be once you get a good edge.) You need to work each stone until you raise a burr on the edge; the burr occurs when the edge is as sharp as it can get on that stone. Then - and only then - go to the next stone and work to an new (more delicate) burr. Once you've gone through your stones, a bit of honing on your strop and you should have a very good edge for woodworking. If you want to shave, you'll need more; I'd suggest you go to one of the straight razor forums for that.

    Caveat: I'm in the school of thought about all this that I sharpen to work wood; I don't sharpen to measure sharpness. Others differ from my view and I'm sure they'll be along very soon. Or perhaps someone has jumped in while I've been writing this; that happens around here, particularly on sharpening threads.
    Last edited by James Waldron; 10-25-2017 at 10:32 AM.
    Fair winds and following seas,
    Jim Waldron

  3. #3
    Thanks Jim for the quick reply. I think I worked my way thru the grits correctly. I spent most of the time establishing the new good edge and when that was complete. I removed the burr and moved on to the next stone. Spent a few minutes on that and then removed the burr. Lapped some more but not as much. Removed the smaller burr. Moved on to the final grit doing the same sequence making the burr smaller and smaller each time I work the stone. Finally removing the final burr on the leather strop. Hope this clarifies. I mentioned the time so as to provide a reference as to how long it took the diamond stone to do it's thing before I could move on to the next stone.

  4. #4
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    I will defer to Patrick to see how he feels about scary sharp using DMT final stone of 8000 grit. He knows what this translates grit wise into sandpaper

  5. #5
    I use the DMT DuoSharp 325 to strip off the old edge, then go directly to an 8000 Norton (or an equivalent Shapton Pro) to polish. No stropping for planes or chisels.

  6. #6
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    John, Just my limited experience is that 1200 to 8000 is a pretty big jump. Also it took me awhile to "brake in" the new DMT diamond plates and knock off the high points for a smoother transition to the next step. My test is if it cuts wood it's sharp. Good luck.
    Chet

  7. #7
    Quote Originally Posted by Chet R Parks View Post
    John, Just my limited experience is that 1200 to 8000 is a pretty big jump.
    Chet
    I did this because of the advise I learned from a pro (cant remember now...). 1200 is suppose to be good enough but the 8000 will really get me to where I want to be. This is what I was told. So, now I am doubting all this...

  8. #8
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    A couple thoughts:

    1. The red compound is fairly coarse IIRC, and is probably makiing your edges rougher than they are coming off of the XXFine DMT.

    2. The DMT plates have well known "rogue particle" problems that cause them to initially leave a rougher finish than their grit rating would imply, but they settle in after a while. It sounds like you may still be in that break-in period.

    3. Even with some break-in, I don't think that an 8K DMT is a particularly good polishing/final stone. It's somewhat coarse at 3 micron abrasive particle size. For reference, JIS-compliant #8000 waterstones are more like 1.2 microns. Diamond is a harsh, sharp-faceted abrasive, so if anything you want to run smaller on diamond than on other abrasive types. When I polish on diamond I typically use a 0.5 um film or paste. The particles in those are both smaller and more uniform than in DMT plates (no "rogue" problems as described in 2).

    Joel Moskowitz at TFWW had some nice blog entries (see links in the article I linked) a while back about sharpening on DMT plates, though note that he finishes on an 8K waterstone. Those may be worth a quick read.
    Last edited by Patrick Chase; 10-25-2017 at 12:49 PM.

  9. #9
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    I lapped the edge on the 325 grit, 1200 grit, then the 8000 grit. I then stroked the chisel on a piece of leather with the red compound on it. My results were sharp chisels but NOT scary sharp.
    Hi John

    The bottom line is whether your edges are sharp enough for your chisels and planes.

    My interest in sharpening is limited to getting edges sharp efficiently, but not necessarily the sharpest. Having said this, I do see issues with your sharpening strategy that could be improved.

    Firstly, diamond (as in diamond stones) can leave quite deep scratches, and removing them with the next stone becomes important: serrated edges are weak edges. New diamond stones are going to create deepest scratches, and the choice of a 325 grit to start makes it especially hard work to remove. My starting stones are either a 1000 Shapton or a worn 15-year old 600 grit Eze-lap diamond stone (which is probably closer to a 2000-3000 grit now). I would ditch the 325 grit stone.

    If you are using a honing guide, I assume that you are sharpening secondary micro bevels. If so, then you can get away with the 8000 grit as the next stone. As raised by James, can you feel the wire edge at the back of the blade? If not, then you are just polishing a turd.

    Now I would try the blade at this point before using the strop. The job of the 8000 is to remove the scratches of the 1200 and polish the edge. If this is so, then the edge you have should be very good. Stropping would take it up a level, however I would not use leather, personally, and rather rub the compound (I prefer Veritas green) on planed hardwood (to avoid dubbing the edge).

    Regards from Perth

    Derek

  10. #10
    Guys, Thanks for the tips. I learned a lot and think I can improve my technique. I am going out in the shop now and try it again.
    I used the 325 course grit because my carpentry chisels had chips and in them. They should have been ground but I wanted to see
    how long it would take for this stone to remove the defects. So this is the reason for this stone. I realize now that the diamond stones
    are very sharp and will leave scratch marks on the surface, as small as they might be. I was using the wrong stropping compound on my
    leather. I should switch to one that is less abrasive or bot use one at all. The link that Patrick supplied (http://www.antiquetools.com/sharp/index.html)
    is good, and it basically spells out all the steps it takes to get a super sharp edge.
    John

  11. #11
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    John,
    In addition, I learned the hard way, Derek and many others are right, Veritas green on hardwood (or MDF) for stropping. One other thing is I always keep a Spyderco ultra fine stone on the bench for quick touch-up's, especially for chisels. I think my chisels take more abuse than plane blades. Just my 2 cents.
    Chet

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