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40/40 vs Swept-back Grind

Discussion in 'Woodturning Discussion Forum' started by Donovan Bailey, Feb 15, 2021.

  1. robo hippy

    robo hippy

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    I am fairly sure it is in the tips and techniques department here, but Dennis Gooding found a way to do it with the varigrind jig.

    robo hippy
     
  2. Karl Loeblein

    Karl Loeblein

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    Thanks. All these different grinds being discussed are interesting, but very difficult to follow without pics and instructions telling how the different angles are measured. I think I understand it enough now to go try this on an older Sorby bowl gouge.

    Btw, If the nose is at 40 degrees then how much difference would it make having a longer swept back wing vice shorter one? In other words, would going with a sharper nose angle improve an Ellsworth gouge without doing away with the longer swept back wing?
     
  3. Doug Freeman

    Doug Freeman

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    SB says they 40 deg wing angle is just as important as the bevel angle to how the gouge cuts. He discusses different grinds and how they cut in this video.
    https://youtube.com/playlist?list=PLdWw7w_lu91QbqyhRXJJ3_N2A-yLymE0W

    A 40 deg true Ellsworth grind gets very thin at the wings - not sure you can actually do it. The Michelsen grind, where the angle stays the same, can be done. I have used it, but not in a while. Not sure how it would compare to a 40/40 for a push cut.
     
    Last edited: Feb 21, 2021 at 8:28 AM
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  4. hockenbery

    hockenbery AAW Advisor Staff Member

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    that would ruin the curve on the leading edge of the wing.

    The strength of the Ellsworth grind is the curve at the leading edge. When doing a push cut with the gouge is rolled up about 45 degrees the leading edge of the wing has a shear angle to make a slicing cut.
    This is sweet spot and yields a very smooth surface.

    Other cuts make use of the curve too.
    Flute up shear cut
    Back cut I learned hjimmy Clewes for square edge
     
  5. Brian Deakin

    Brian Deakin

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    The best web link for Stuart is

    http://www.dmwoodturners.com/?page_id=642

    Further there are a number additional videos on YouTube of Stuart turning and sharpening which have been added in the last 3 months


    View: https://www.youtube.com/watch?v=nOHgxQPFNBs&ab_channel=RSUPublicTV



    View: https://www.youtube.com/watch?v=ROfafTjf2kU&t=3s&ab_channel=DeniseSawyer


    and a sharpening video

    View: https://www.youtube.com/watch?v=fhlMQr7Hk0k&t=18s&ab_channel=DeniseSawyer


    Additionally Cindy Drozda has several sharpening videos which may be helpful

    https://www.youtube.com/results?search_query=cindy+drozda+
     
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  6. robo hippy

    robo hippy

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    Hmm, Tim no longer has his Robust AB..... Now, he has a Stubby. Emeliano, is that the same Stubby you have????

    robo hippy
     
    Emiliano Achaval likes this.
  7. Timothy Allen

    Timothy Allen

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    @robo hippy, Although the date indicates Tim's video was uploaded in January 2021, a quick search suggests that episode originally aired in 2009 -- I think the Stubby pre-dates Tim's Robust lathe.
     
  8. Donovan Bailey

    Donovan Bailey

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    Good catch. I think that you are correct. It is always a pure pleasure to see Stu operate with a gouge in his hand. I sincerely look forward to the day that he is able to travel around a bit and conduct workshops again.
     
  9. Bill Blasic

    Bill Blasic

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    Tim sells Robust I don't know what he did with the stubby.
     
  10. Brian Deakin

    Brian Deakin

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    Allen Mattsen likes this.
  11. robo hippy

    robo hippy

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    I did contact Tim, and he told me the story... I am very curious about the Stubby lathe, but haven't had a chance to turn on one. Love Tim's sense of humor....

    robo hippy
     
    Emiliano Achaval likes this.

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