Kevin Kelly

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    Boston, Massachusetts
  1. Violin geometry references

  2. Violin geometry references

    OK, how about this? You want to use a violin bridge template for a violin, cello template for cello, etc. and you may want to make the string heights higher or lower for some reason, etc. The template is already done because it’s been figured out how it works, and you can make whatever modifications you want and make your customer happy. What i use is exactly that - a template that can be modified, so if you want to make something different you don’t have to start from scratch each time, and the result will always look “right”. I'm moving my studio, so I can't take photos of stuff right now, but here are a few fiddles I made. Can you tell these shape were drawn with a compass?
  3. Violin geometry references

    Some thoughts about this thread, in no particular order - The video that was linked to above was made by me some time in the last few years in response to an irritating discussion on MN, actually, and I think the point I was trying to make was that any discussion about this kind of thing is only relevant if it can produce a usable, useful result, in the real world, and that if you can’t prove that it works in real life, you should maybe not claim that it does. Since then I’ve tried to avoid the topic since it seems to antagonize some people (especially me). Not that I have a problem with it, but the Strad did not ask me nor tell me about posting the video on their website. Actually, I thought that I deleted it shortly after posting it, and was surprised to see it still around. If I’d known they were going to use it, I would have put a little more effort into it. Marty has published some work on violin design, but for some reason he seems to have forgotten to include himself in his list earlier in the thread. I really hate the word “geometry” in this context, because its modern meaning is confusing to any discussion about violin design. Any reasonable amount of reading on the subject would make it clear that Francois is correct when he says that in the age of Andrea Amati “geometry” was nothing other than measuring. Nothing mystical, and not really anything to argue about. The fact that there have historically been so many bad hypotheses about a specific theory or system doesn’t mean there wasn’t one - there was. I disagree that theory doesn’t matter to modern makers. It may not matter to all makers, but I think it’s exactly like saying that music theory doesn’t matter to musicians - they can learn to play by ear, so why do they have to bother with all that theoretical stuff? The way we all learned to make violins is like playing by ear. “Here’s a thing - copy it. Why does it look like this? Well, that’s just the way it’s done.” What I want is violin making theory, so that i can understand the forms I’m making and change them if I want, and still make something that’s traditional. I feel like it’s respectful to do that, and it gives me a feeling of freedom to make whatever I want. I like it when someone looks at an instrument I made and says - “Amati?” or “which del Gesù?” Finally, here’s what I’m working on right now. I recently decided to make a “copy” of a del Gesù violin (not a real copy of, but based on, a really nice fiddle). I took some measurements from said fiddle, plugged them into my little system (just like in the above-referenced video), and, using proportional dividers and a straightedge, drew a template for a mold (again, following the Andrea Amati recipe in the video - very simple). Here’s a picture of a quick tracing of the template with and without a washer to draw the edge, laid over a photo of said fiddle. Now - does anyone here want to tell me that I don’t know what I’m talking about?
  4. Perpendicular does not exist on violin tops...

    At the risk of opening a can of worms, I think that the concept is much simpler - it's that the bridge divides the angle of the strings over the bridge. In other words, if you were to draw a line that divides the angle that the strings make when they go over the bridge in half, that line should go roughly down the middle of the bridge. On violin this almost always works out if you make the back of the bridge perpendicular to the plane of the ribs, but that's a result of the given parameters, not a parameter itself. That's also as far as you can lean it back without it looking very scary. If the force vector of the strings is not contained entirely within the bridge, it will be guaranteed to warp.
  5. Casein glue and ground

    Berl, When I worked for Roland Feller in SF he told me that at Wurlitzer's they used Borden's white glue to glue in cleats, but that was before they changed the formula. My understanding is that it used to be casein glue, and now is some kind of plastic.
  6. Digital Amati project

    Hi Torbjörn, I don't know about the first question, but I'm sure it's possible. I don't use the outline function myself. As for the second one, no way. I'm all done with the video demonstrations. I did have Harry nearby to show me how to use it, though, and that really helped. I will admit that at first I was not interested in doing so, but I'm glad I eventually did. I agree. However, in the end the geo engine does the same thing as a divider and straightedge. It just saves a lot of time if you do a lot of drawings.
  7. Digital Amati project

    I should say that the Geo engine is easily one of the most important and useful tools that I have. It may not be for everyone, but if you can manage to figure out how to use it, it's a powerful game changer.
  8. Digital Amati project

    Harry can correct me if I'm wrong here - The program that does the drawings is called the Geometry Engine, which is a program that Harry wrote. It's basically a digital version of a compass and straightedge, but you have to be able to describe the relationships between centers, arcs, and lines in mathematical terms. The idea of a visual ruler and compass already exists in many forms, like SketchUp, for example - I've used that heavily, but you have to know how to dumb it down to use it because the defaults are for doing much more complicated 3D rendering. There are other free programs out there to do similar things, although it's been so many years since i looked I don't know what they are now. The real benefit of using the Geometry Engine to me is that it is programmable, which means you can describe the relationships among the various parts of the drawing and then easily manipulate them. In other words, in the program that I use (I wrote my 'four circle' thing into the geo engine) I can, for example, change the width of the waist, which automatically changes the location of the points of the corners, which in turn changes the arcs of the curves of the corner blocks. To do this by hand takes some work, but on the computer it is just changing one number. Last month I was sans computer for a week, and I had an encounter with an amazing violin, which I decided I had to "copy". This meant deconstructing the design, which I did using pencil and paper, but it took me about 4 hours. If I had my computer it would have taken less than 10 minutes - and I could have just printed out a drawing at the correct size to make a template from. There are some parts of the program specifically for violin makers - for instance Harry has created a function that will add a margin to a finished mold shape, so if you draw the inside of the ribs it will create an outline based on that. You can also instruct it to measure between any parts of the drawings.
  9. Digital Amati project

    The program creates a drawing in pdf form, and the scale is in mm. You can compose a drawing with the program and print it out at the correct size.
  10. Perry Sultana...

    They must be friends by now...

    To connect two previous posts - the oldest orchestra in the US is the Handel and Haydn Society in Boston, which was so named because they performed the old classics and the new stuff (Handel and Haydn) in 1815
  12. Moving across the country for violinmaking school!

    I'm not on the way, but your cat looks an awful lot like mine, except for the eye color, and maybe the attitude... Best of luck to you and your wife, KK
  13. Pechenart, Violon "L'idéal"

    That's pretty awful. I would guess the inspiration may have come from a Stauffer-style guitar head like this one
  14. violas from violins

    I guess that I would want to see the fiddle in person. It is described as a composite - and something was done to the belly to make it fit - but I wonder if the back was cut or not. Not to get too far off the original topic, but my point is that the shape of the Strad CV is one that's part of the Cremonese repertoire. It just doesn't normally show up in violins, and when it does it looks funny, like the upper bouts are too small. Here's the image of the back from the Tarisio website compared to a photo of the front of the Brusilow del Gesù (about 140 years apart). and here it is compared to a Jos. fillius cello (here the corner layout and approach are different, obviously)