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Thread: Neck block / join shape

  1. #1

    Default Neck block / join shape

    Hello everyone,
    I'm about to start my first mandolin build, a copy of an A4 Gibson and i'm not entirely sure about the way the ribs/neck block area is shaped.
    On some photos it seems the neck block along with the ribs is curved like this:

    sideview of the body (neck block is on the left):
    Click image for larger version. 

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    this would form the apparent curve seen for example here:
    Click image for larger version. 

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    But this seems impossible or extremely hard to construct with a dovetail joint.

    Is this just an illusion caused by the "V" shaped neck heel and the ribs are in fact upright? Or was this really done on some mandolins?

    Many thanks for any clarifications!

  2. #2

    Default Re: Neck block / join shape

    Yes, it is because the neck is wider at the top and thus wraps further around the rims.

  3. #3
    Registered User sunburst's Avatar
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    Default Re: Neck block / join shape

    Quote Originally Posted by _Ra View Post
    ...Is this just an illusion caused by the "V" shaped neck heel and the ribs are in fact upright?...
    Yes.

  4. #4
    Registered User j. condino's Avatar
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    Default Re: Neck block / join shape

    The two hardest thing in the learning process for me were getting great dovetail joints and good finish work.
    www.condino.com

    Crafted by hand in a workshop powered by the sun.

  5. #5
    Registered User Rjayh's Avatar
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    Default Re: Neck block / join shape

    Graham McDonald's book covers laying out and cutting a dovetail joint for mandolin neck - could be worth a look! https://www.mcdonaldstrings.com/mandolinproject.html

  6. #6

    Default Re: Neck block / join shape

    You need to look at this perspective and see that the neck heel isn't a straight V but curved to meet the back overlay squarely. This plus the fact it's meeting the curved sides of the body give the curved look when viewed from the side.
    I hope I'm answering the right question.
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

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  7. #7

    Default Re: Neck block / join shape

    In school we used to learn about conic or cylindrical sections in geometry classes. I am not sure if it is taught anymore. The intersection of a straight plane with a cylinder will produce a parabola or ellipse depending on the angle. You are intersecting a cone and a cylinder but the same principle applies. That is why it looks curved

    Click image for larger version. 

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  8. The Following 2 Users Say Thank You to CarlM For This Useful Post:


  9. #8
    Registered User j. condino's Avatar
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    Default Re: Neck block / join shape

    Excellent response Carl!
    www.condino.com

    Crafted by hand in a workshop powered by the sun.

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