Don Noon

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About Don Noon

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    It ain't rocket science... it's more complicated
  • Birthday 03/20/1952

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    Male
  • Location
    Carlsbad, CA
  • Interests
    Acoustics
    Violin construction
    Varnish
    Old-time fiddling

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  1. You could also increase lateral stiffness by turning the wood 90 degrees... which is what bearclaw probably does, to a mild degree. You don't get extra lateral stiffness without giving up longitudinal stiffness.
  2. The only thing I actually timed was the clearing off of the central area, as it was noisy and I left the shop until my timer went off. The cutting took about 8 minutes per pass, and I took 4 passes. Most of the time is taken in setting up and checking the results; the cutting goes pretty fast. But even with all the setup, it's infinitely faster than I can go by hand (but maybe not faster than Burgess). These were my first plates, so caution slowed things down, I think. With more practice and less caution, I can probably wreck plates in a flash. If you loft using "rails" (as I did), I think the result is similar to the curve network.
  3. I looked very carefully under glancing light at the parts that were milled from the model, and I could see no evidence of ripple from the model. Either it's just a rendering artifact, or something else that doesn't matter. I only care about the wood things.
  4. Yes... but the upper and lower bouts required a lot of thought to make profiles at an angle that would blend properly with the long and cross arches. I can't answer whether any other program is better, as this is the only one I have ever used to try to do these complex compound curves. I know there are 2 videos on YouTube showing how to make plate models in Fusion360 with the sculpting function, but I gave up on that method after a short time. Seems totally wrong to my way of thought and what I want to accomplish.
  5. After figuring out (con)Fusion360's file arrangements, I finally got some 3D modelling done. This is just the center area of a viola back plate, not including the figure-8 low point of the plate, which I do separately. There are some artifacts in the rendering, which don't show up in fabrication. And here is the first back plate off the machine. There is a centerline arch groove which I milled previously... then I changed the arching design for the 3D work, so I'll fudge it in the fingerplane and scraping stages. This is all I really want to get done on CNC: get off most of the wood, get the geometry established without messing around with templates, and get the outline and purfling groove done. I don't mind getting off the last mm or two by hand, and even WANT to have that hand-finished final result. Now I have to figure out how I want to do the hollowing. For sure this first set will be the old way (by hand) until I settle on the concept and make the tooling. At the moment, I'm thinking I should hollow out the inside first.
  6. That's trees for ya... they do what they do, regardless of what you want.
  7. The method I use for measuring speed of sound was first discussed in this thread. Thanks for the offer to send wood to test, but I think you can do this yourself if interested. As for why some wood has strong late growth, I can only guess that the winter conditions might be good for growth... not too cold that growth shuts down, and maybe good sun and rain as well. But I don't know. I don't think that the hard growth is a structural problem, but perhaps (but not necessarily) an acoustic difference. Although I have encountered it enough times to become convinced that wide winter growth tends to have lower speed of sound, the one set that I have with the highest speed of sound (6500 m/s) has very strong winter growth lines. I would expect high density and low speed of sound to primarily hurt the high frequencies. But again, I don't have enough real experience to say for sure, just a few examples. Torrefying tends to darken wood, so the denser winter growth (which is dark because of the high percentage of wood vs. air) tends to get very dark, or visually "harder". Wood that starts out with a relatively low speed of sound generally tends to improve more, percentage-wise, than wood that starts out with a higher speed of sound, but it still doesn't "catch up" to the good stuff.
  8. The photo isn't detailed enough to tell if we're looking at a wood crack or an open center seam, although it's a bit raggedy so at least some wood looks like it has been split off. I expect center pins can be done in ways that might cause a crack... i.e. using a tapered pin, and hammering it in. I presume this would be the method used for inexpensive, high-production instruments. I use a steel pin for locating a top for assembly, but then remove the pin and glue in a slip-fit piece of wood to fill the hole (but not pin it to the endblock). I can't imagine that a crack would be caused by this type of pin.
  9. Not a cause, but a contributing factor: wing tips are cantilevered crossgrain features, so in addition to the violin corners, the wing tips are the most delicate features that can get broken off by accidental impact or force. As to the most likely sources of impacts on the wing tips, I don't know... but if it's more common on the treble side, I'd suspect diddling with soundposts.
  10. Thoughts and measurements I have some... but not experience. From what I have seen, a large percentage of winter growth tends to be dense and have a low-ish speed of sound... which might or might not mean anything as far as the sound goes. I haven't actually used any of it for an instrument, since (for the moment) I tend to use high speed of sound in medium-to-low density wood. Did you check the speed of sound before you started?
  11. I guess I feel good about getting the PMV11 blade when I ordered my Veritas plane. I have it now... but haven't honed the blade down for use yet.
  12. Agreed... that way I don't have to do it (and I didn't feel like doing it anyway). As complicated as all of that is, it's incomplete as it doesn't evaluate the player and bow effects. It's really more complicated. Or, as Marty suggested, you can simplify by just making violins.
  13. Just another Strad... with a lot of things going on in one small area. This photo is a section in the steepest part of the C bout arch of a 1-piece back. The rays in the middle of the photo indicate that the wood was cut fairly far off-quarter. On the left, the varnish is worn off and the pores/vessels are filled with dirt. On the right is colored varnish with random chinks filled with dirt. Between the wood only and colored varnish zones is probably a clear ground, which fills the vessels and prevents them from filling with dirt.
  14. "Pores", or more specifically vessels that are cut at the surface, always run parallel to the longitudinal grain, and they are relatively large open pits or channels. Rays are even larger, but composed of bundles of very fine tubes that run perpendicular (mostly) to the rest of the grain. The ray tubes are so fine that I never see much get into them, much less dirt. This is a well-known Strad (ex-Jackson) where you can see the dirt-filled vessels and the lighter rays that have not been dirtied. The center joint is in the photo, so you know which way the grain is running, and there is no original varnish left in this photo.
  15. Those definitely look like rays to me, not stained pores. Rays are clear(ish) bundles of fibers/cells with a different orientation than the main wood, and can look light or dark depending on the lighting. One photograph can be misleading. This is the same bridge, with different light directions: