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jim mcavoy

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About jim mcavoy

  • Birthday 07/08/1940

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    peru,ma usa
  • Interests
    violin - bagpipes - doing things by hand - music theory and doing things that 'can't' be done (red hot dagger)

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  1. This also works when using a little skill and is equal to a light tap with a felt hammer
  2. sometimes working on an old Junker too ....it is, for me, an 'in situ' application
  3. yup....my knuckles tend to be a little tender ....arthritis
  4. these are designed to shed and have to be replaced...not a big deal they are consumed more by re-flattening ..it's just a finishing stone... pressure is quite light
  5. I use a 'home brew' hard felt hammer at about 7 grams +/- ..it is non resonant and won't mar the finish ... a striking mallet from a piano would also work ...the convention is to soften it with olive oil on old mallets (I like 3 in 1 oil...it doesn't harden up as much) The thinking is that with a hard mallet you also hear the striking head resonance (and the impact) I find a knuckle to be variable Edit...I use this for evaluations mostly Jim
  6. perhaps you are simulating the pressure of the strings (to some degree) to see what else moves or doesn't move?(in the static state)...kind of like mini-turning moments?
  7. this is bench learning .... make up some practice pieces various sizes and shapes (violin like segments)and play with them 1)First blush...stop when good enough 2) it follows mass and stiffness...try it on a bow (dampened) to see what it is like
  8. nodes and anti-nodes a super simple explanation :(see watch it) http://www.physicsclassroom.com/class/waves/Lesson-4/Nodes-and-Anti-nodes
  9. the procedure here,for me, is with a thimble lightly tap on a dampened plate (you only hear the wood) To adjust sand or scrape accordingly, It doesn't take much to get an (uniform) increasing or decreasing tap tone .....You are really hearing the taper and the tap tone is rather subtle, and the pitch is quite high I also use this on a cheap bow that has problems...Quick fix .....(I got this from another member on this forum, who will speak up if he wishes) a few licks with 600 grit sand paper or the same thing with a scraper makes a big change! soft ground: in concepts, one is adjusting mini-nodes on a progressive spring Jim
  10. good advice and the clue is building to stiffness ....It works for some, but not all I believe no two builders would use the same technique (flexing)to arrive at a finished violin...not something that can be packaged and sold on the street corner....It is learned at the bench , and only then if any one builder can do it at all! the trick is to get off home base, some can And others can't ..... There are other ways to get to the same point
  11. This is soft ground for me...I think it is an over-view to see how the plate is coming, if there is an evaluation, it is subtle (but there)
  12. Why not ...if you use colored caulk on a plate and overcoat it with spray lacquer you have a lasting record... best if there is no color key
  13. Davide, have you spent any time looking at the transitions (flexing)in the lower bout ...longitudinal, torsional, and traverse bending ...say using clock points 3 to 9? (I and 2 points at a time) (and conversely in the upper bout) ....not for a 300 pound gorilla Jim
  14. I know this is a reach....Have you drilled down in the production of sound to see if this applies ....I'm thinking in the areas of self replication complete with accidents
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