40/40 on a Tormek

Discussion in 'Woodturning Discussion Forum' started by Jon Spelbring, Oct 25, 2017.

  1. Jon Spelbring

    Jon Spelbring

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    I tried out Batty's 40/40 grind earlier this year, and I like it - more for heavy spindle work than for bowls, but I'm not trying to start a debate. As a new Tormek owner, I was wondering if anyone has been able to replicate the grind, and if so, what Tormek/SV-186 settings did you use?

    Thanks!
     
  2. Bill Boehme

    Bill Boehme Administrator Staff Member

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    If I knew what the 40/40 grind looked like, I think that I could figure out what settings might work. If you could describe how to freehand it that would give me an idea if it could be done.
     
  3. RichColvin

    RichColvin

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    This jig can get 40 degrees angle; don't know about the 2d 40. See the 3d entry below.

    IMG_8308.jpg

    Rich
     
  4. robo hippy

    robo hippy

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    It has to be done free hand and/or on a platform. 40 degree bevel, and 40 degree sweep/roll to the side. I am fairly sure that the reason it can't be done with a jig is because you get a different sweep/roll effect/angles. To me it doesn't make much difference, but I haven't used jigs in years... I do consider it to be a bowl/detail/spindle gouge combo tool, rather than specifically for bowls or spindles.

    robo hippy
     
  5. Bill Boehme

    Bill Boehme Administrator Staff Member

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    So it sounds like the wings aren't very long and that the edge angle on the wings might be about the same as the nose angle.

    To Rich and Jon, several years ago I did some experimenting with the three settings of the SVD-185 and although there is a lot of interaction I figured out the main effect of each setting. My recollection is a little fuzzy, but I think that the following is what I found, but don't take it as gospel:
    • The JS (0 to 5 jig setting, or 0 to 6 on the new SVD-186) primarily controls the roll axis of the tool and therefore can be used to control the wing profile ... use 0 for bottom feeder with short wing and 6 for Ellsworth grind with long wing.
    • The nose angle, α, is mainly set with the distance of the bar to the stone.
    • And, I think that P (protrusion of the tool through the jig) determines the wing edge angle ... more protrusion gives a fatter edge angle on the wings.
    Based on these recollections, I think that the third grind shown in Rich's post might be close to what you want, Jon.
     
  6. Jon Spelbring

    Jon Spelbring

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    Thanks for the replies! I have a feeling Robo Hippy is right as far as the wing angles are concerned. I may try the 3rd pic in the Tormek diagram, but with JS of 1 vs. 2 and see what happens.
     
  7. RichColvin

    RichColvin

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    Jon,

    The Tormek SVD-186 manual has some information that may be useful for this endeavor. Look at page 82.

    Rich
     
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  8. john lucas

    john lucas

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    Actually the wing angles will change based on the shape of the flute as well as how you grind it. Grinding by hand on the tormek works fine. I have been playing with sharpening the 40/40 (mine is actually 45/45) on the Tormek, and strip sander and my CBN wheels. All are done a platform with lines etched in at 45 on both sides to show me where to start the grind. All work just fine.
     
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  9. Bill Boehme

    Bill Boehme Administrator Staff Member

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    I just accidentally stumbled across an old post by John Lucas on using the Varigrind jig and Wolverine fixture to approximate the 40/40 grind. This ought to help as a starting point for figuring out a similar set up for the SVD-186 on the Tormek. Here is the link: 40/40 grind with Varigrind
     
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  10. john lucas

    john lucas

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    Yea I forgot about that post. That was a fun experiment. Of course it was much easier if you had a 40/40 grind to start with so you could put it in the jig and match the shape.
     
  11. Jon Spelbring

    Jon Spelbring

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    Thanks, Bill!
     

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