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Graduation plans

Discussion in 'Setup & Repair [DB]' started by MIKMAN, Mar 26, 2009.



    Mar 4, 2008
    Larisa, Greece
    Dear friends, i've been donated an old work horse, a fully carved double bass with many war scars. It seems to be constructed in Central Europe, possible Czech Rep. or Hungary, and after serving decently an orchestra in Athens retired as decorative item in a well known bar. After redecorating the place the owne donated it to me and now i have to deal with it. Taking the top off i fixed all the seams etc and it is almost back in shape. However the top is very thick and i'd like to regraduate it. I have A. Wake's graduation plan but i'd like to know if there are any other plans in the market. Do the Chandler's plans contain graduations? Are there any other material available? I think our respectable luthiers can help a lot.
    Thanks in advance
  2. scotty77


    Jan 31, 2008
    Victoria, B.C.
    I've got the William Tarr plan from Chandler and it does have the graduations marked on the plan. I believe they all did.
    A few years back, Strad magazine had posters with dimensions listed as well. I can't remember if they had a bass poster or not. Check their website to see if one's available.
  3. Matthew Tucker

    Matthew Tucker Commercial User

    Aug 21, 2002
    Sydney, Australia
    Owner: Bresque Basses, Sydney Basses and Cellos
    How can you tell that it needs graduating? if it is old and has many scars it may have a respectable history of active use, implying a good bass, just as it is.
  4. Darren Molnar

    Darren Molnar

    Nov 6, 2007
    saskatoon Saskatchewan Canada
    humble instrument maker
    thick does not always mean bad.
  5. arnoldschnitzer

    arnoldschnitzer AES Fine Instruments

    Feb 16, 2002
    New Mexico. USA
    This subject comes up every so often and always elicits side-taking and self-righteousness. In my opinion, regraduation can be a life-saver for an instrument that does not work in its current state. Or, if it was built wrong (there, I said it) and needs to lose some weight so it can vibrate. These things said, one has to pay attention to numerous factors which all affect each other as regards graduations. For example; arching, wood density and stiffness, grain width, size of bass, age of wood, recurve shape, type and thickness of back plate, etc. An amateur or a repairperson without serious building chops ought not to get involved in regraduating an older instrument unless it is of little value. And obtaining a chart of one particular maker's graduation numbers does not prepare a person to perform this kind of major invasive surgery. That said, typically bass tops run 7-12mm thick in the center and 4-6mm in the outer regions. But deciding how these regions are mapped out, and adjusting the resulting tap tone of the plate, is where experience is crucial. Makers all do it a bit differently. There isn't really a right and wrong.
  6. Wow,

    I don't post here often in this sub-forum but I read with interest what the master luthiers have to say. Just wanted to say thanks to all our highly esteemed luthiers. You are indeed artists. I always learn something in this sub forum.


    Mar 4, 2008
    Larisa, Greece
    I feel privileged to have my thread answered by all of you an particularly by our esteemed luthiers. Well, the decision for graduation came after measuring the thickness of the top plate and finding that it is too thick in the various areas, compared with my other double basses (old and new). It is an instrument about twenty five years old and typical example of the Eastern European school. My experience in double basses is limited to minor repairs but i have regraduated twenty violins and six violas of the same school with excellent results. I believe that the resonance and the vibration of the top plate will be certainly improved and i have all the necessary gadgets to make a good mode matching. If it was an older instrument i wouldn't dare to touch it but it is not the case, so... God help me.
  8. james condino

    james condino Spruce dork Supporting Member Commercial User

    Sep 30, 2007
    asheville, nc

    Thanks for your input with the numbers. How often do you see a bass that is in the 7mm range for the center of the top plate? That number sounds incredibly thin- I've hack'd a lot of archtop guitars that are that thick, and even seen a few very overbuilt mandolins close to that range. It is my understanding that there are a couple of well known builders who don't graduate the top and it is a fairly even 6-7mm across the entire range, from the recurve to the center.

    The only thing I dislike more than an unresponsive thick overbuilt top is doing major repairs to correct the damage that occurred from someone regraduating it too thin and having it fall apart...

  9. arnoldschnitzer

    arnoldschnitzer AES Fine Instruments

    Feb 16, 2002
    New Mexico. USA
    I'm working on an old English bass now that measures about 6mm all across the top. It's Panormo school, and the other Panormos I've seen are similar. The arching is quite high and the wood is heavy and tight-grained (from virgin growth, no doubt). Believe it or not the top has no sinkage or deformity. But most basses are 8-9 or 10 in the center, depending on all the variables. There are some modern makers going thinner, some of whom combine a thin top with doubled linings. This is a recipe for disaster, in my opinion.
  10. ctregan


    Jun 25, 2007
    Syracuse N.Y.
    Depending on where I "tap", it seems there are many different tones that can be produced. Is there one spot in particular that when tapped will produce the tap tone you are looking for?
  11. arnoldschnitzer

    arnoldschnitzer AES Fine Instruments

    Feb 16, 2002
    New Mexico. USA
    I don't try to tune the plate to a specific pitch. I'm usually holding the top loosely by a corner while thunking it in the bridge area. I'm trying to get a certain tone and decay which leads to the overall sonority I'm looking for. It's way different with and without the bass bar.
  12. Eric Rene Roy

    Eric Rene Roy

    Mar 19, 2002
    Mystic, CT
    President: Upton Bass String Instrument Co.
  13. ctregan


    Jun 25, 2007
    Syracuse N.Y.
    Thanks for the description Arnold and for the use of the word "sonority".

    [Sonorous, (definition) - imposingly deep and full; capable of producing a ringing sound.]
  14. ctregan


    Jun 25, 2007
    Syracuse N.Y.
    Thats what dragged me on to this slippery slope in the beginning :)

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