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back braces

Discussion in 'Setup & Repair [DB]' started by basswraith, Feb 16, 2006.


  1. basswraith

    basswraith

    Mar 10, 2003
    Boston
    I wanted to shoot this one out there. Has any one had experience or have any preferences to X bracing in flat backs rather than cross bars?
    What are the differences in function ?
    And what are the pros and cons?
    I have some Idea , but my ideas are not based on experience yet.
    Any feed back might make this a topic worthy of discussion.
    Thank you.
     
  2. John Sprague

    John Sprague Sam Shen's US Distributor

    Mar 10, 2003
    Rochester, NY
    Sales Manager, CSC Products Inc.
    Well, we like the theory. The whole idea is that a cross brace expands in the opposite direction of the back, pulling the back apart. The X brace expands more in line with the back, so less stress. It's been working pretty well for us, we sold alot of them over the years with only a few needing later repairs. For flatbacks, where you expect more problems than a round back, we're very happy with the track record.
     
  3. It seems like a good idea, but all I know is the back on my X braced Shen is slowly but surely caving in. It was around 1/4" concave when I got it new seven or eight years ago, and now it's a good inch or more sunken in the center. I'm just waiting to see what it does, out of curiosity. Maybe one day it'll just implode? :hyper: Might be exciting!
     
  4. M_A_T_T

    M_A_T_T

    Mar 4, 2004
    Canada
    Theres been a discussion about this before, you should search for it. The way I look at it is acoustic guitars are generally braced on the back with cross braces only.

    If I ever make a flatback bass, I would probably use cross braces, but I would borrow the method quite often use in guitar building (which I used to do) where the entire back edge of the sides has a radius shaped into in and the linings, and the back cross braces have the same radius cut into them, so the back has a slight arch to in, stabalizing it. Look at an acoustic guitar from the side and you'll see what I mean.
     
  5. KSB - Ken Smith

    KSB - Ken Smith Banned Commercial User

    Mar 1, 2002
    Perkasie, PA USA
    Owner: Ken Smith Basses, Ltd.
    I thought the X-brace from Shen was a new thing in the last 3-4 years. I didn't know it's been going on so long.

    I have one Bass with an X-Brace that was added sometime in the mid 19th century in New England. http://www.kensmithbasses.com/DoubleBasses/MysteryBass/name_that_bass.htm

    This Bass is getting a complete restoration with two exceptions. The Bass Bar is tiny and may be the original but the Top is in perfert form and about 12mm thick in the center so it stays undisturbed once again. http://www.kensmithbasses.com/DoubleBasses/MysteryBass/100_0066.jpg
    http://www.kensmithbasses.com/DoubleBasses/MysteryBass/100_0078.jpg
    http://www.kensmithbasses.com/DoubleBasses/MysteryBass/100_0084.jpg

    The grain or the Top wood is the tightes I have seen on any string instrument. One could go blond counting the rings but with some counting and a calculator I estimate about 350 rings each half of the bookmatch. That's one strong piece of 'european iceage' wood!

    The X-Brace is also in great shape so we won't disturb that either.
    http://www.kensmithbasses.com/DoubleBasses/MysteryBass/100_0085.jpg
    http://www.kensmithbasses.com/DoubleBasses/MysteryBass/100_0074.jpg
    http://www.kensmithbasses.com/DoubleBasses/MysteryBass/100_0077.jpg

    Although there are some cracks in the Back and many in the Top, the original form of the Bass is well preserved. Perhaps Basses like this are ones we should study. The Back did have several Crossbars before including a twin set at the bottom but someone must of thought his 'X' design would improve the Bass somehow.
     
  6. I purchased the Shen in either '97 or '98, so that would put it around seven years or so. It's the 7/8 gamba cornered model and was one of the first few I had seen at the time.
     
  7. KSB - Ken Smith

    KSB - Ken Smith Banned Commercial User

    Mar 1, 2002
    Perkasie, PA USA
    Owner: Ken Smith Basses, Ltd.
    I got my first Shen at the 1997 Nashville Namm show. It was one of two 3/4 Gamba Gemunder model Basses they made at the 1000 model level. Similar to the 800 model at the time but without Chinese wood. Mine is a round Back and can be seen here; http://www.kensmithbasses.com/ft/assemblysection/stress.html

    It's the only pic I have of it. It was my first Bass after not having one since about 1990 when I put my 18th century Italian Bass up for sale. It was no replacement by far but a good start getting back into the Double Bass. My eldest son Jon is using that Bass now for College. He traded with his younger brother who was using it for the 7/8 Shen I have. My youngest is no longer playing due to his interest in Computers so I have the 7/8 as a spare for gigs that I wont take one of my oldies out on.
     
  8. KSB - Ken Smith

    KSB - Ken Smith Banned Commercial User

    Mar 1, 2002
    Perkasie, PA USA
    Owner: Ken Smith Basses, Ltd.

    Ok, if you think any of what I posted was not of any value here, I can delete it.

    As far as the X goes, most great Basses in the world have regular Crossbars on the back. Some of the great Basses have the X but the mass majority of Basses in the world have the standard 3 or 4 cross bars. If your Bass is having a problem, then it's worth a try. If not, leave it alone. I personally have never had a problem with a Flatback as far as the crossbars go.

    The Shen that I saw had a slightly rounded back with an X brace in it. That's the first time I've seen that.
     
  9. jmpiwonka

    jmpiwonka

    Jun 11, 2002
    my shen willow has is the flatback and it has the X brace of course. the back does swell (very slightly rounded) just a little bit in the center too, and the shape is fine, no sinking or anything. the label says 2004 i think.
     
  10. arnoldschnitzer

    arnoldschnitzer AES Fine Instruments

    Feb 16, 2002
    Brewster, NY, USA
    All braces attached across the grain of the back are wrong. That includes x and cross. Seasonal wood movement creates extreme tension resulting in cave-ins, loose braces, and back cracks. So choose your poison.
     
  11. jmpiwonka

    jmpiwonka

    Jun 11, 2002
    what kind of brace do you use for your flatback basses mr. Schnitzenager?
     
  12. KSB - Ken Smith

    KSB - Ken Smith Banned Commercial User

    Mar 1, 2002
    Perkasie, PA USA
    Owner: Ken Smith Basses, Ltd.
    So Mr. Arnie, is there a solution or just the nature of the beast? Does the seasoning of the wood help to avoid this in any way if both the Back and Bar materials are old, well aged and well acclimated?

    My Loveri seems as if it was not well seasoned while the Dodd, Prescott and Mystery Bass seem to have had minimal damage from shrinkage in the 200 year average of each Bass. I would assume those Basses were made with well seasoned wood. It's always the seasoning that helps bring out the flavor.. :cool:
     
  13. Jeff Bollbach

    Jeff Bollbach Jeff Bollbach Luthier, Inc.

    Dec 12, 2001
    freeport, ny
    You're not asking Ahnold to give away his secrets now, are you?
     
  14. basswraith

    basswraith

    Mar 10, 2003
    Boston
    If the perpendicular positions of the cross bar grain to the back cause damage over time, is it possible to use a back brace that spans across the back like a regular cross bar but with the grain of that bar running in the same direction of the back? Of course it would be hard to find a tree that large for that piece of wood but if both grains are running in the same direction would there be less of a conflict? Im not sure it would transfer the vibrations across the bass as well but who knows?
     
  15. KSB - Ken Smith

    KSB - Ken Smith Banned Commercial User

    Mar 1, 2002
    Perkasie, PA USA
    Owner: Ken Smith Basses, Ltd.

    If he has a secret on this, it must be in his vault at the Bank or Mars! He just did 2 flat Backs for me and re-glued the center seam on another. This never came up. Is he saving it for some other special bass?.. I'm hurt...:crying:
     
  16. jmpiwonka

    jmpiwonka

    Jun 11, 2002
    lol, he knows you'll take it back to him if it poses problems. it's like a security measure :D, just kidding, we all know he wouldn't do that on purpose.
     
  17. arnoldschnitzer

    arnoldschnitzer AES Fine Instruments

    Feb 16, 2002
    Brewster, NY, USA
    It's the nature of the beast. A few things can help, though: VERY dry wood, weak glue, leaving room near the back's edges for some movement. Expect the crossbars to come loose and deal with it.
     
  18. Freddels

    Freddels Musical Anarchist

    Apr 7, 2005
    Sutton, MA
    I guess that a hybrid would be the way to go with a flatback.
     
  19. basswraith

    basswraith

    Mar 10, 2003
    Boston
    I know a modern bass maker who puts a cross bar in a round back, under the post area. I wonder if the back will experience any of the complications discussed earlier....Im sure minimaly if at all as these basses are very well made. I have enjoyed each one I have tried The sound is mature , powerful and of high quality.
    I wonder if the maker could throw in his 2 cents on this concept..cross bar in a round back.
     
  20. M_A_T_T

    M_A_T_T

    Mar 4, 2004
    Canada
    The braces wouldn't be nearly as strong.

    EDIT: Just thought of something: What if you only glued the braces at certain areas, like instead of painting the entire underside of a brace with glue as you glue it in place, you apply glue only to little one inch sections every couple inches, so the brace technically isn't attatched to the entire section of the back? Or glue down little cleats every few inches and glue a brace onto that?