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Thread: E.A. Berg chisels dull extremely quickly - what am I doing wrong?

  1. #16
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    Quote Originally Posted by Niels J. Larsen View Post
    I kindly ask you to elaborate on how to perform such a test :-)

    I suspect that you mean that the chisel should be hardened in such a way that it takes some effort to file away material from the chisel, but I'd like some details on what result I should expect in either a good or bad scenario.
    A file will easily cut through soft steel, it should pretty much just slide or roll over hard steel.

    Quote Originally Posted by Niels J. Larsen View Post
    As I wrote earlier I've tried two different 10mm chisels albeit both E.A. Bergs.

    I have other chisels, but would it matter if the width is not the same?
    I assume a chisel of smaller width would not see the same pressure on the edge, but I could be wrong?
    A smaller chisel being pressed or hit just as hard will have a smaller area to disperse the pressure at the edge. A small chisel would likely deform quicker than a large chisel unless my understanding of physics is flawed.

    jtk
    "A pessimist sees the difficulty in every opportunity; an optimist sees the opportunity in every difficulty."
    - Sir Winston Churchill (1874-1965)

  2. #17
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    Alright, applied a file to the already dull chisels and it slid across the steel, so it seems they are not that soft.

    I will try again with 30 degrees and softer wood. Let's see what happens:-)

  3. #18
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    Fineness is not what I'm referring to. I don't have time to explain at the moment but the long and short is that less aggressive abrasives make a more durable edge. Please research this if you are curious, it has been discussed at length.

    Some woods are harder on tools, when I work certain woods I know I'm going to be spending some time sharpening after the fact

    Experience is a factor, chopping bevel out (shearing cut) is very hard on the edge, take a light cut, like 1/64".
    Bumbling forward into the unknown.

  4. #19
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    I have some Sorby chisels that require a 35* bevel to prevent rolling the tip edge over when chopping in hard material. I don't think 30* is enough if your chisels passed the file test.
    David

  5. #20
    I have never used a Berg chisel, never used sandpaper for sharpening, and never worked shedua. However, I had the same reaction as Brian, that the sharpening was the problem. A brash sharpening medium will leave deep scratches which leave the edge vulnerable to damage. And the damage may not all be cleaned up the next honing. For strength we like a smooth edge, not a jagged edge.

  6. #21
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    After just two or three cuts, the bevel is rolled over and the chisel is dull and useless.
    An edge that rolls is more likely to be soft steel (or too low a bevel). An edge that is serrated (perhaps due to the honing media) is more likely to chip.

    Regards from Perth

    Derek

  7. #22
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    Quote Originally Posted by Warren Mickley View Post
    I have never used a Berg chisel, never used sandpaper for sharpening, and never worked shedua. However, I had the same reaction as Brian, that the sharpening was the problem. A brash sharpening medium will leave deep scratches which leave the edge vulnerable to damage. And the damage may not all be cleaned up the next honing. For strength we like a smooth edge, not a jagged edge.
    How can I verify if the edge is smooth or not?
    The edge is sharpened with finer and finer grits until it has a mirror finish, but I don't have a magnifying glass so perhaps it's not smooth enough.

    I don't see how using something other than (extremely fine) sandpaper with identical grit would help me get a better edge but I might be missing the point completely. :-)

  8. #23
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    Quote Originally Posted by Niels J. Larsen View Post
    How can I verify if the edge is smooth or not?
    The edge is sharpened with finer and finer grits until it has a mirror finish, but I don't have a magnifying glass so perhaps it's not smooth enough.

    I don't see how using something other than (extremely fine) sandpaper with identical grit would help me get a better edge but I might be missing the point completely. :-)
    What grit steps are you using from start to finish?

    The chisel is sharp enough to shave hairs from my arm if that tells anything....
    Shaving hair from your arm has different steps. To me the highest degree is the chisel removing hair in such a way as it feels like the edge is rolling over the skin and you do not realize it is cutting hair until you see the clean swath it left. Next in line would be it leaving a clean swath but you can feel the hairs being cut. After that a few hairs are left and you can feel it on the skin, and so on down to it not cutting but a little hair. Cutting a little hair is sharp enough for some of woodworking tasks. For fine pairing or smoothing plane blades it is better to go for the higher degree.

    The lesser sharp while still cutting hair may have a bit of a rough edge. That is why it snags the hair.

    Though one member at one time claimed they could sharpen with 80 grit and shave hair with the edge. My bet is it would not be a comfortable shave.

    Some razor sharpeners use a hanging hair test with similar grades of cutting to determine sharpness. The recent "New Toy" thread was about a machine to test sharpness.

    I remove most of the waste with my fret saw so there's only 1-2mm waste left for the chisel.
    A sharp chisel should be able to pare end grain, even in harder woods.

    On the chart found with a Google search on shedua, it doesn't look to be much harder than various American oaks.

    Maybe try paring away the waste to see if there is better edge retention.

    jtk
    Last edited by Jim Koepke; 05-26-2017 at 2:04 AM.
    "A pessimist sees the difficulty in every opportunity; an optimist sees the opportunity in every difficulty."
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  9. #24
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    Niels, there is nothing "wrong" with your sharpening and the edge produced. I am not saying that an edge produced as per Brian and Warren does not have advantages or is not better; I am saying that an edge produced your way is good enough and should not lead to the symptoms you describe. Hell, carpenters on job sites sharpen chisels on belt sanders, then pound them into hard woods, and this works. Either the steel on your chisels is too soft, or the wood is too hard. Increasing the bevel angle is all you can do. Try 35 degrees.

    Regards from Perth

    Derek

  10. #25
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    Totally jumping outside my area of expertise and experience, but, I remember people discussing wood that had something in it that caused it to be brutal on tools. In my mind, it had to do with where it was grown, but that could be so totally wrong and my brain may be playing tricks on me.

    Obviously, there can only be a few possibilities:


    1. It is the wood, it is just brutal for some reason. Try a similar, but different wood; For example, some white oak. You could also send a sample piece to someone else to give it a go.
    2. The metal in the chisel is bad / soft / whatever. So try another chisel, totally different brand, borrow a chisel, etc. Also, it has been suggested that you can try a file against the chisel, but you need to figure out where you should test the steel. Off hand, I would think that you would want to test near the edge, but then you need to rehab the edge. If it is not near the edge and if only the cutting edge has the soft steel, then testing elsewhere will not tell you that.
    3. Related to chisel prep somehow. Let someone else prepare that one. If it is the prep and you prepare a different brand chisel, you might see the same results with a perfectly fine chisel.


    Sadly, given your location, it is not easy for me to say "here, try one of my chisels" or even to have you send me the chisel to prep it for you.

  11. #26
    here's my take on the risk with using diamond abrasives for finishing edges:

    hard steels tend to be notch sensitive. that is, a sharp inside corner presents a point for fractures to begin. Some tool steels are tougher than others, but as a general statement the harder a given steel is heat treated to the more brittle and the more notch sensitive.

    the shape of an abrasive is a a factor in the performance of an edge. very sharp abrasives like diamond make deep, V bottomed scratches. more smoothly shaped abrasives like the garnets in coticules cut shallower, more flat bottomed scratches.

    where the sharp V scratches left by diamond abrasives intersect the edge of the tool they present microscopic notches which present origin points for microscopic fractures. the harder, more brittle the steel and the lower the bevel angle (thinner edge) the greater the risk. the result from the user's perspective is that the tool dulls prematurely.


    in the case of the O.P. of this thread, the tool was dulling by folding over, so probably a different dulling mechanism at play.

  12. #27
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    in the case of the O.P. of this thread, the tool was dulling by folding over, so probably a different dulling mechanism at play.
    Maybe it is time for the O.P. of this thread to tell us more about their sharpening regimen.

    Is it flat bevel, hollow grind, Seller's convex bevel or some other method?

    jtk
    "A pessimist sees the difficulty in every opportunity; an optimist sees the opportunity in every difficulty."
    - Sir Winston Churchill (1874-1965)

  13. #28
    I expect Derek is correct, this isn't a sharpening problem. It's a steel problem. The chisels are old and at some point in the past someone may have gotten a little gay with a grinder. While a higher bevel may help, if it doesn't the chisels need either grinding past the soft steel or re-harding.

    ken

  14. #29
    Not sure if it has already been mentioned, but shedua is known to have a high silica content: that can't be doing your edges and good.

  15. #30
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    Quote Originally Posted by Jim Koepke View Post
    Maybe it is time for the O.P. of this thread to tell us more about their sharpening regimen.

    Is it flat bevel, hollow grind, Seller's convex bevel or some other method?

    jtk
    I used a single flat bevel for the 25 degrees, then a microbevel or even a second bevel at 30 degrees.

    I'm not dismissing the chisels yet as I'm now trying to grind/sharpen the chisel all over again from scratch i.e. re-flatten the back etc. to be 100% sure everything is in order (although I was sure before but, well...)

    Let's see if that changes anything.

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