Kevin Kelly

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About Kevin Kelly

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  1. Hi everyone, Some time ago, somebody on MN posted an image of an X-ray of the Stradivari Tenor in Florence. I've been trying without success to find that thread. Does anyone remember that and/or know who posted it? Thanks, and Wishing everyone good health - KK
  2. I'm not aware of any online source that has anything like the info on the poster. Personally, in your case I think €40 is worth it. A lot of work went into that poster by thoughtful people. You say you have a workshop and tools, so you should be able to swing it, if you want to try to do a decent job. Just spend the money. The poster has a lot of info that will answer questions that you have not thought of yet.
  3. For what it’s worth my own observation about cremonese instruments is that the plate that gets glued first is flat, and the one that gets glued second is tapered, so guitars, for example, where the belly is glued to the ribs before the back, have a flat surface for the belly and a tapered surface for the back, and a violin is the opposite. If I’m not mistaken, I think Roger Hargrave’s explanation was that the taper had to do with the neck set, which was not 90 deg., but more like 87 (or something). Placing the tapered rib of the upper bout flat on the bench (with a spacer for the edge thickness) and fitting the neck heel to that angle before nailing sets the neck with that angle. I’ve done it and it works. To attach the neck of a guitar, you place the ribs and belly structure upside-down on the bench, with an overhanging tongue of spruce sticking out where the neck goes, and place the neck upside-down on the tongue ( with a spacer under the rest), and fit and nail the neck to the rib structure, so the neck is in the same plane as the belly.
  4. That doesn't look so bad. The fact that it's long and along the bass bar makes it more expensive to fix than if it were short and not along the bass bar, but it's totally fixable, and looks worth fixing.
  5. https://www.bbc.com/news/world-middle-east-50600025 As far as whether this fragment came from a Stradivari, I don't know - but if it did it would be interesting because there seems to be no pin for the back
  6. There are a lot of things about that fiddle that look like Paris to me. If that’s the case it would have had a through neck and there’s usually some kind of monkey business around the upper block area of the plates which your guy should be able to see when he has the lid off (removal of some of the flat platform for the neck root and built-up wood at the sides of the upper block).
  7. I think it would be safe to say that almost every violin that has ever been sold has been polished many times, either with alcohol/shellac/x , or wax. The problem behavior from the Moennig shop wasn't really "polishing", it was applying an overcoat of glossy varnish. Duane beat me to it. It's become a verb, although I say "Moenniged".
  8. Well, this looks familiar. Here it is one more time. I think my step-by-step explanation from a few pages ago is easier to understand though. Anyone can play along with a compass and straightedge No computer required.
  9. Good morning Francois, I think maybe one of the differences in interpretation is that in my reading of it, the curve of the body between the widest part of the lower bout and the c bout circle doesn't follow the "plan". If that is actually the case it makes it harder to pin down the arc. I'm ok with that, I just think that particular area is open to the maker to deal with in their own way - an idea that I think also carries over to violin making. The reference measurement for all these constructions is the radius of the lower bout. You are right - the body length is a product of the process, not a starting point for the design. I understand that it's a strange idea and contradicts the history, but that's how this system works. It delivers a shape that automatically flows well, and in the end the length always turns out to be fine anyway so it turns out not to be a problem. It may not be the way Stradivari designed it, but for my purposes I think the drawing matches the instrument very well, and I would use it to make a mold (in fact, I just might ). This is why I like this system - it delivers what I think is an elegant solution to a problem that quickly gets me extremely close but still leaves room to make adjustments.
  10. Yes, I would agree that it is nice to have.
  11. Hi Francois, The proposition is the same one, just drawn by a computer instead. The values are exactly as described. The program follows the same steps I described in the last post. The "extension" is the addition of some length to the lower bout circle in order to move the center of the c bout circle farther up the body. The purple circle in the diagram is the lower bout radius plus the extension, which you can see is 1/3 of the lower bout radius. in this system, the c bouts must be tangent to the waist and the upper and lower bout circles . The guitar has such a wide waist, it would make the body too short - so the extension is added to make the body a better length. If you want even more length you can add a longer extension, or add one from the upper bout as well. Not used much for violins, but normal for guitars and other plucked instruments. the first "measure" is the lower bout radius or the lower bout diameter, which is arbitrary. All of the other measurements are some ratio of that. Everything needed to complete the design is listed in the previous post.
  12. Kevin is busy with the kids and work... I will take you up on this one, but then I think I will go back to work for a while. Quattro Cerchi Recipe: Upper to Lower, 4/5 C = Lower Waist = 4/5 Upper turn 2 lower = 2/3 L turn 2 upper = 3/4 U extension = L/3 1) Draw a horizontal line for the diameter of the Lower Bout. 2) Draw Lower circle, add second turns and make a center line 3) Draw horizontal lines for the center of the c bout parallel to the center line, at a distance of W+C 4) establish the center of the extension, 1/3 of the radius of the Lower bout 5) Draw an arc w/radius L + ext + C from the center of the extension in the lower bout (opposite side from the c bout) 6) The intersection of the circle (step5) and the lines (step 3) is the center of the c bout 7) draw the c bout arcs 8) draw circles from the center of the c bouts w/radius C+U. The intersection of these arcs is the center of the Upper bout 9) draw the upper bout circle and a horizontal line through the center 10) draw the second turns of the upper bout 3/4 radius of the upper bout 11) draw the end blocks. In this drawing the lower block is from the top of the lower bout circle and the upper block is from the narrowest point (which is a mistake - it should be from the bottom of the upper bout circle - it was modified from a different design and I missed it) the stretch between the c bout and lower bout circles is up to the maker to deal with however they see fit. That's it.
  13. what would it look like, I wonder, if instead you scaled the lower bout widths to be the same?