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  1. #91
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    Quote Originally Posted by elanjacobs View Post
    I found some old Berg chisels in the boss's bench a while ago and thought I'd sharpen them...the grinder just chewed through the steel. I'm sure there must be a reason behind their reputation, stuffed if I can figure it out though
    Human beings are inclined to magical thinking. They're also highly susceptible to manipulation via propaganda. My observation is that these factors weigh heavily on the modern woodworking market.

    I was born in the 60's. I remember that the plastic toys of the era broke very easily. Plastics these days are much better. Remember the movie The Graduate?
    Innovations are those useful things that, by dint of chance, manage to survive the stupidity and destructive tendencies inherent in human nature.

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  3. #92
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    Rob,

    Thanks for the thread and the focus on data. I know there will be a lot of people who say "But but but" .... Data is data.

    At the risk of starting a fight - I will say this of the old tool users I know.... Most will admit that you have to hunt to find a good, old chisel. The age and label maker aren't definitive.... And these fellows turn many "desirable" chisels over to collectors in the hopes of finding one more truly good user....

    I am not surprised by the large spread in performance. I have experienced the same results on wood... Where 2 chisels of very similar hardness work very differently...

    On some chisels requiring reducing force for successive cuts... Perhaps the wood is polishing the steel or slightly relieving the steel around carbides on the bevel - resulting in lower forces for a few successive cuts... The other chisels are likely rolling the edge or chipping very slightly.. This could be why there is a sharp increase over 1 or 2 cuts... I frequently experience this paring end grain spruce.. Drives me nuts.... But I ended up happiest with a harder, slightly chip prone chisel - honed with whatever microbevel finally stops the chipping.... Then it goes away and the chisel cuts right and works beautifully... I have given up hope for the too-soft ones... Lap the back and it rolls a teeny bit more the next time...

  4. #93
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    I started doing this because I didn't know. Everybody in the woodworking world has an opinion about what makes for a good chisel but the breadth of positions, absence of consensus and the lack of depth supporting those opinions frustrated me.

    As I mentioned above, I plan to put some of the weirdo self sharpening chisels under the scope and look to see if I not changes. I know of a local place to get EM done but at ~$1500 a sample it's out of my price range.
    Innovations are those useful things that, by dint of chance, manage to survive the stupidity and destructive tendencies inherent in human nature.

  5. #94
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    Rob

    You may need an EM for looking at metallurgy, but not for the purposes of just taking a closer look at an edge.

    A good digital microscope with 200 magnification will reveal a great deal about an edge and they are much cheaper.



    Sent from my ZTE T84 using Tapatalk
    Stay sharp and stay safe!

    Neil



  6. #95
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    Here is an example of x200 digital microscope image of an edge, first from the side and second looking straight down on the edge (the image covers an area of approx 1mm wide). In the second image, the edge runs vertically mid way through the metal shown on the right. The metal (I have forgotten which one) was polished down to #12,000 grit.

    Scraper - polished to #12000 - before burr.jpg

    Scraper - 200 X - no burr - edge on - 2.jpg

    Any microchips or rolled edge will be readily seen at this magnification.
    Stay sharp and stay safe!

    Neil



  7. #96
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    Default Hardness data for four additional chisel types



    I think that the Woodcraft crank chisels are made by Henry Taylor. a new low in hardness.
    Innovations are those useful things that, by dint of chance, manage to survive the stupidity and destructive tendencies inherent in human nature.

  8. #97
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    A fun exercise would be to run your data through an ANOVA to see how many "distinct" categories of hardness and chisel penetration you really have...

    Just a glance would lead me to believe maybe 3 or 4 distinct groups...


    I typically end up with chisels lumped like this:
    Too soft
    Soft but usable
    Perfect
    Really hard

    Cutting performance I would similarly rank:
    Useless
    Rolls very lightly on end grain but usable if you keep lapping the back - cutting degrades quickly in certain applications. Chisel is still useful
    Very good cutting performance
    Awesome.

    And as your data shows - there is not a very good correlation except at the ends of the distribution.... Eg: very hard and very soft...

  9. #98
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    After I get studies done, particularly after I have the dataset I'm planning on chisels I make under conditions that I control I think there may be some trends showing up.

    At this point I really know very little about the metallurgy of the chisels I've tested. The LN's and Blue Spruces are A2. The Japanese chisels are probably carbon steel. The second best performer, Craftsman, is 'forged alloy steel' which could be pretty much anything and it's not particularly hard.

    I'm grouping the chisels by performance: Garbage, Usable but nothing to write home about and Impressive.
    Innovations are those useful things that, by dint of chance, manage to survive the stupidity and destructive tendencies inherent in human nature.

  10. #99
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    Quote Originally Posted by rob streeper View Post
    I'm grouping the chisels by performance: Garbage, Usable but nothing to write home about and Impressive.
    really like this categorization
    regards from Alberta, Canada

    ian

  11. #100
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    Default Edge retention data for three more chisel types

    Innovations are those useful things that, by dint of chance, manage to survive the stupidity and destructive tendencies inherent in human nature.

  12. #101
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    This is how I rank them.

    No apparent correlation of hardness and edge retention ability.
    Innovations are those useful things that, by dint of chance, manage to survive the stupidity and destructive tendencies inherent in human nature.

  13. #102
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    Default Analysis by region of origin



    Assuming of course that Britain is part of Europe. I've left off the Lee Valley PM-V11's because, though I suspect that they were made by Crucible Industries (:rucible Industries:: Our Products) in New York, I don't know for sure.
    Innovations are those useful things that, by dint of chance, manage to survive the stupidity and destructive tendencies inherent in human nature.

  14. #103
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    Innovations are those useful things that, by dint of chance, manage to survive the stupidity and destructive tendencies inherent in human nature.

  15. #104
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    Another thing I would love to see in the ANOVA is the between vs within and correlation of hardness within the same chisels to cutting performance.

    The ANOVA allows you to see the effects of a "soft" LN vs a hard LN compared against a soft Buck vs a hard Buck....

    My own experiments on re-hardening chisels show some truly huge differences in chisel performance when you take a too-soft chisel and harden/temper it a few points higher... BORG Buck Bros. Chisels are particularly impressive in this regard.... Out of the package they are pretty miserable.. But Q&T them with a 425F temper and they are fantastic....

  16. #105
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    If you don't mind telling here what's your temperature program?
    Innovations are those useful things that, by dint of chance, manage to survive the stupidity and destructive tendencies inherent in human nature.

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