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Thread: Trammel of Archimedes for oval rosettes

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    Default D'Aquisto's Trammel of Archimedes for oval rosettes

    Last year I did some backstage work at The Metropolitain Museum of Art; incredible place and really nice people to work with. While there, I was able to blueprint the D'Aquisto mandolin in their collection.

    The following day, I was at John Monteleone's place getting in a few laughs, playing a few tunes, and getting an earful while picking his brain about the restoration of that mandolin. He showed me an interesting tool that had quite a lineage: Originally acquired by D'Angelico, passed down to D'Aquisto, and then to Monteleone. It was based upon a mechanical double cut way that produces an ellipse and is often attributed to Archimedes. I wrote an article on it for American Lutherie magazine last year. I have never seen a commercial unit like this available for sale, and if or when one comes up for sale, I'd guess that I just did a number on increasing the selling price, and John is holding on to his. I keep trying to convince him it is time to pass it on to some younger fellow with the right last name to keep the story going; something like John to James to John to James sounds about right!

    I have only had to make a couple of oval rosettes for restoration work; for those I made a series of inside and outside templates and then just cut everything by hand. I've also first cut the soundhole and then used a grammil to scribe the perimeters for the rosette referenced off the soundhole. I have a student who is building a Selmer style guitar with the small "scream" type rosette. Is there any mechanical system available that Selmer style builders use with a router / laminate trimmer / dremel attached? A similar setup would work for old oval hole Gibsons, Martins, et cetera. A search didn't find any.

    Thanks for the help.

    j.
    www.condino.com
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    Last edited by grandcanyonminstrel; Mar-06-2015 at 10:41pm.

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  3. #2
    Registered User Timbofood's Avatar
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    Default Re: Trammel of Archimedes for oval rosettes

    James, do you have an illustration of this instrument (the trammel, not mandolin)?
    If it works the way I think it does, there are old fashioned oval mat cutters which use the two axis type of adjustment, some thirty plus years ago we had one at the frame shop where I worked. I had not thought about the use for at least marking the oval hole outline, I miss that job. Didn't make a ton of money but, it was one seriously fun gig!
    Just googled it, similar to the ellipsograph mat cutter which was all "overhead suspended" as opposed to resting on the surface. With your woodworking skills I wouldn't think it would be miserably difficult to make.
    Timothy F. Lewis
    "If brains was lard, that boy couldn't grease a very big skillet" J.D. Clampett

  4. #3

    Default Re: Trammel of Archimedes for oval rosettes

    It is the same principle- two independent channels that cause an elliptical rotation. Many of the introductory 3d printing systems have them as a default program and call them "do nothing machines" when they are not hooked up with a purpose. There are a number of handheld ways to get the job done. I'm interested in one with a motor, but not so fancy that I have to write a CAD file!

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    Registered User belbein's Avatar
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    Default Re: Trammel of Archimedes for oval rosettes

    I regret to say that I looked this up on line, and found this under the title "The Wonky Trammel of Archimedes." It's the cat that made me run screaming from the room to hide under my bed:

    This article provides brief notes on an ancient problem: the ellipsograph of Archimedes. It was generalized
    in the seventeenth century using geometric techniques, and problems of this kind provide very
    interesting puzzles in later school or early university problem solving courses, e.g. [3]. These mechanisms
    are of direct relevance to contemporary mechanical engineers. The mathematical treatment we
    provide here, albeit in outline form only, is to alert readers to the power of the polynomial Gr¨obner
    Bases techniques for providing explicit solutions to problems which appear intractable. This is a late
    twentieth century technique which combines the pure mathematics of rings and groups with the power
    of computer algebra.

    Imagine a cat sitting in the middle of a straight ladder which stands on horizontal ground while resting
    against a vertical wall. If the end of the (thin) ladder GW slides down the wall at W then the (point
    sized) cat C0 follows a circular path.


    http://web.mat.bham.ac.uk/C.J.Sangwi...nkyTrammel.pdf
    belbein

    “Years ago my mother used to say to me, she'd say, ‘In this world, Elwood, you must be oh so smart or oh so pleasant.’ Well, for years I was smart. I recommend pleasant. You may quote me.”

    See my latest blog post: http://www.mandolincafe.com/forum/en...lay-for-People

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    Registered User PT66's Avatar
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    Default Re: Trammel of Archimedes for oval rosettes

    My friend teaches machine shop at a local community college. We are both former machinists. He also have built a few guitars and ukuleles. I showed him the article in American Luthierie. He built a similar widget the you can screw a dremel into and is adjustable for the size of oval. He is about to use it on a uke. Will let you know how it works.
    Dave Schneider

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    Registered User bernabe's Avatar
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    Default Re: D'Aquisto's Trammel of Archimedes for oval rosettes

    Quote Originally Posted by grandcanyonminstrel View Post
    I keep trying to convince him it is time to pass it on to some younger fellow with the right last name to keep the story going; something like John to James to John to James sounds about right!

    www.condino.com
    When can I pick it up?

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    Registered User sgrexa's Avatar
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    Default Re: Trammel of Archimedes for oval rosettes

    I have nothing to add to this interesting conversation other than to note that this mandolin must have been made before Jimmy's later "anti plastic binding" phase. It is indeed still "superfly despite the six ply" I must say!

    Sean

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    Registered User PT66's Avatar
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    Default Re: Trammel of Archimedes for oval rosettes

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ID:	131549 I love oval sound hole. I just like they look. I use aluminum templates and a Dremel router base. I have 3 sizes of templates. I designed the in Pro/e and had a local machine shop do them on their CNC. The instrument is a tenor guitar I just finished 2 weeks ago.
    Dave Schneider

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