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Graduation Thickness of Top Plate

Discussion in 'Basses [DB]' started by Craig A., Sep 8, 2005.


  1. Craig A.

    Craig A.

    Sep 8, 2005
    Greetings, New here. I'm trying to locate images of, and recommendations for various thickness of the quadrants of the Top Plate. Any related info would be helpful.
    Thanks, Craig
     
  2. nicklloyd

    nicklloyd Supporting Member/Luthier

    Jan 27, 2002
    Cincinnati, Ohio
    Welcome to Talkbass... someone will probably ask you eventually: can you fill out your public profile with a little more background information?

    Top graduations aren't usually mapped out in quadrants. The thickest part is under the G foot, above the post... between 7-10mm. The chest area is then slightly thinner 6-9mm, then it becomes thinner in the upper and lower bouts 4-7mm. Top graduations all depend on arching height, arching style, and the particular characteristics of the piece of spruce you have on hand.

    Are you building a bass?
     
  3. Craig A.

    Craig A.

    Sep 8, 2005
    Nick, Thanks for the reply. I bought a Mittenwald that is in pretty poor shape. I bought Chuck Traeger's book and am trying to learn the ropes of repair. I took off the back and put it back on. I've since taken off the neck and the top. This bass is for my learning. Trying to get as much as I can out of it and will hopefully end up with a better bass. I went throught the steps with a tone generator to see what the mode 5 nodal pattern was. I'm now trying to see if I can improve upon the nodal pattern by altering the thicknesses on the top. I'm drawn to bass repair and will pursue making it a profession. I'm also having to shim the neck up, the angle of the fingerboard is too low. It's at about 3 1/2 inches and I'm going to bring it to 4 inches from the top. It's a pretty complicated job now requiring shims on both sides of the neck butt. The cheeks of the mortise are pretty thin as well. Whoever worked on it before used all the wrong kinds of glue so it's been a challenge. What I've been reading refers to the top and back plates as having four "circular" quadrants each with a center the size of a fist. The thicknesses increasing outward from the center of each quadrant. They then thin out at the outer edges where the carving begins on the upper and lower bouts. The thickest areas being the around the f holes and down the middle at the glue line. Well, thats my take on it. I was hoping to find some visual guidelines regarding the graduations. Sounds like you build/repair. From what you explained, I better get some other books. Thanks, Craig
     
  4. Craig,

    First let me say that I support your enthusiasm but not at the expense of making permanent changes to an old instrument. If you insist in using an old instrument to learn restoration, you would do better by adhering to the general rules and guidelines of professional luthiers.

    You say you want to end up with a better bass, have you heard the bass as it was? If not then better than what? What if you improve upon the nodal pattern of mode 5 and the bass implodes when strung up to tension?

    There is a lot of information here and elsewhere, so do some research please and I am sure any of the professional luthiers will be able to answer specific questions. But for now, I would suggest you halt, gather some more information and then proceed systematically.
     
  5. Jeff Bollbach

    Jeff Bollbach Jeff Bollbach Luthier, Inc.

    Dec 12, 2001
    freeport, ny
    Ken is quite right. Regraduation is for when all else fails.
     
  6. Whoa, scary territory there Craig.
    "Learning the ropes" takes many years and the oversight of someone more knowledgeable. I'm a repair dabbler too, I have Traeger's, and Elgar's, and Chandler's books, and while they all contain worthwhile information, they don't tell the whole story. There are things you must learn by doing, and things that will require your ingenuity. The guidance of an experienced pro is invaluable. There are repair jobs I wouldn't consider, like a neck graft, a post patch, regraduation. Done poorly, they could reduce a decent instrument to firewood.

    Has an experienced luthier seen your bass? Have you had a second opinion that suggests regraduation?
     
  7. KSB - Ken Smith

    KSB - Ken Smith Banned Commercial User

    Mar 1, 2002
    Perkasie, PA USA
    Owner: Ken Smith Basses, Ltd.
    Re-Graduation can also be done if the measurements are un-even or as in a Round Back, about 1/3rd too thick as was my Morelli. Both my Morelli and Hungarian Bass (during it's 5er conversion) were discovered to have been left un-even and also too thin in spots. The Back was 14mm in the center as well on the Morelli. Depending on the condition of the Top caution is advised. Like Ken and Jeff tell you, be careful where you step!

    Factory/Shop Basses are often left either heavily wooded, Thinned too much at the start and/or un-even either way. Older Basses may well have had some help during it's life from other Repairers/improvers! As long as you can fix what you break, go for it. A new 'Bass Bar' is usually needed after Regraduation so make sure you start by taking out the old Bar b4 carving any wood away. It may also be part of the Top as well aka 'integral'. This too is common of German Shop Basses.

    Have fun..
     
  8. Craig A.

    Craig A.

    Sep 8, 2005
    Thank you for your replies. I'm grateful for your cautionary warnings. I take your comments to heart, and recognize that I am traveling in potentially dangerous waters. I would never attempt any of these repairs on some one elses instrument. I bought this bass at a pawn shop for $500. The asking price was $1000. The back was only partially connected to the ribs. It had lots of problems. I bought this bass to learn repair; my Bass 101. Gentlemen, I've made many mistakes along the way but I've learned so much. I don't have a teacher, there is no class for me to take. My support team are books and the internet and I'm ever grateful for their guidance. I've had it together. I liked it's sound better than my Hoyer, which I like a lot. I bought this bass for an education, and my education continues. I'm doing my best to make the wood sing. It's what brought me here. With your help, I'll succeed. Thank you for your guidance and encouragement. Craig
     
  9. Hi Craig, this is a late post to this question but I found this and thought it might offer some insight. I agree with all the cautions you have received so don't take this as a suggestion of what you should do, but as an example of one makers strategy. Mr. Hitchings site has much other useful information as well but here is a clear photo of a top plate with the thicknessing map clearly drawn on it:
    http://homepages.enterprise.net/gwyllum/bass/cbasstophollowing.html
     
  10. bejoyous

    bejoyous

    Oct 23, 2005
    London, Ontario
    Hi
    You should check out the book, "So, you Want to Build a Bass." by Peter Chandler. If you do a google search on either the title of the book or Peter Chandler you'll be able to find it. He has about a dozen models of basses in the book and you can order plans etc.

    Brian Joyce