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Shunyata

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Everything posted by Shunyata

  1. I make my own violins and fit my own bridges... $20 for a good quality blank and an hour of fussing to get the profile properly fitted to the violin. I would charge more than $45!
  2. Someone said, "I'm find it amazing that some people don't seem to grasp even some of the most simple mechanical principles." As a mechanical engineer who has done his fair share of finite element deformation models, I agree - but not necessarily in the way you mean. The bottom line is the deformations are complex, in multiple directions, not just one. But with some basic thought you can rank the first order effects. Bridge compression is significant, end folding is not. The f holes tend to concentrate bridge deformation in the center of the plate so "bulging" is not heavily driven by the bridge. Conclusion is that instrument profile have BOTH intentional design changes in the arching and deformation. I don't see why this should be controversial.
  3. Agreed... there is no way that "folding" distortion - bringing neck and tail together - can cause flattening of the top. In fact it would cause buckling of the top and an INCREASE in arching!
  4. Some of the difference in arching that I am seeing likely would not arise from string load on the plate. I make the assumption that load would tend to flatten arching. The profiles I am seeing actually tend to concentrate increased curvature at the upper bout widest-point. As a mechanical engineer, I don't see how this would occur solely through load. If course that does not mean the historical shapes are undistorted. But there is more than just distortion going on.
  5. Looking at the other discussion, I can see this topic is a real can of worms. The short answer seems to be that what I am seeing actually exists in old instruments. Whether I should duplicate it is another matter. I will simply note that the instruments I make with a flatter top profile sound good... perhaps this is answer enough.
  6. I would like to make sure I properly understand a subtlety. The long arch has a high point in the middle of the plate and slopes down to the top and bottom edge of the plate. For backs it seems like the arching is typically symmetrical - the top-side arch and bottom-side arch are mirror images. For bellies it seems like the bottom-side arch is very similar to the back. But the top-down arch is rather different. The belly top-side arch seems to stay flatter as you move from the center, then fall more steeply once you cross the upper bout wide point. Do I understand this properly?
  7. FFT is designed to detect independent components. I there are two fundamental tones, that is what FFT will find. Your ear also hears the sum of those two fundamental tones, which is often perceived as "beats'. But mathematically FFT is incapable of hearing the beats.
  8. This is where the difference between artistic and pecuniary influences shows up. I am an ameteur with an overly romantic view of violin making. But even my shop has a bandsaw and a drill press.
  9. My bad. It is Strobel that refers to scoop as a "non essential nicety". Johnson and Courtnall instructs one to produce a "hollow", no more than 1mm on the G string side - with some passing acknowledgement to making room for string vibration. J&C also talks quite a bit about assymetry in the radius and scoop, aiming for a subtle and efficient profile.
  10. I am an enthusiastic amateur, so pardon my ignorance about scoop. The texts I have read (e.g. Johnson and Courtnall) seem to imply that scoop is "optional", not strictly necessary, but some players seem to prefer it. I haven't seen that it is essential for talented, vigorous players. (I can only vouch for myself, an untalented, vigorous player.) Then again, I haven't tried to solo over a full orchestra. I suppose a lot has to do with the nut height on the G string, too. If you wanted a super low nut height, an extra 1mm of clearance in in the scoop could be important.
  11. I have made finger board with flat profiles and constant-radius curvature. I don't see any difference in playability or interference with strings. My opinion is that scoop is just an accidental artifact of constant radius templates.
  12. The geometry is a simple conic section. If you use a constant radius of curvature at every point along the length of the fingerboard you will automatically wind up with a hyperbolic "saddle" around 1mm deep. (I measure by putting a straight edge against the fingerboard surface and measuring the maximum gap.)
  13. Always worry about starving the joint. Squeeze out is easy to clean. Some of my early projects broke apart when carving out the backsides of the plates... From too little glue to get a good joint. I always clamp my joints using bar clamps. I know some just rely on rubbing the joint but I would not advise this approach.
  14. Some suggestions for reference point include: * edges of top block (when end pin is out), * inserting a vertical reference stick through either f hole, located at a consistent point. *looking at post angle versus back plate at the point of contact (deliberately ignoring the appearance of the post overall) * using a flat shim to measure position of post relative to f hole notch, both N-S and E-W. * bending your post setter so it is at right angles to garland when post is in proper location. None of these are scientifically precise, but together they produce rapid, repeatable results. And that is all we really need to achieve... quick, consistent placement that is in the right neighborhood for fine adjustment.
  15. Old Growth refers to trees that grew, from the time they were a seedling, under a well established forest canopy. These trees are forced to reach upward toward their light source, grow more slowly, tend to have very straight grain, and an absence of knots because there are few branches below the crown of the tree.
  16. Yes I have noticed this, but I also figured out its a function of your visual reference point. There are multiple surfaces on a violin, all at different angles, and the sound post isn't square to any of them except the garland, which isn't much help. Your process will be most repeatable if you deliberately compare the sound post position against a specific reference point(s) on the violin. This keeps your brain from using whatever you looked at last as the reference point.
  17. Plane, then scrape. Order of operation is everything! :-)
  18. As a followup to this thread, I have found that using a toothed, convex finger plane results in a very nice surface (after scraping) even on tightly curled maple flames. This was my first adventure with toothed blades. What a wonderful invention!
  19. Shunyata

    Tanning

    I use 60W UV LED floodlamps from Amazon. They seem to be marketed for dance floors and parties. They are about $30.
  20. A little off topic, but that purfling channel carving is wonderfully neat and clean. Can't help but express my admiration... nice work!
  21. Thank you for the comments. My violins have a very fine texture to the varnish surface associated grain of the flames. I always assumed this was considered bad form. But i am hearing from you all that is simply the marker of "hand made". I am happy with that answer. I know the theory about slaked plaster, but I always find it lessens the flames so I avoid it.
  22. I find that tightly flamed maple results in a slightly pitted surface, even when you use sharp instruments. After finishing this results in a fine texture to the finish. How do people handle this issue? Or am I doing something wrong? Fillers, like plaster, are one approach but I hate the deadening of the flames that comes with it.
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