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Interesting comments from Rick Turner re. graphite necks/neck stability

Discussion in 'Hardware, Setup & Repair [BG]' started by The Mock Turtle Regulator, May 26, 2002.

  1. (Rick Turner- former Alembic luthier and co-founder, BP columnist)

    (the subject concerns possible neck instability with Zon graphite-neck basses)

    from The Bottom Line;

    Subject: Dead Spots/Graphite & heat

    As Bill Bolton rightly pointed out, mass relationships between neck/peghead
    and body greatly affect dead spots and their opposite, wolf tones. But
    that's just half the picture. The other huge issue is stiffness, and this
    is why I (along with many other luthiers) put graphite in wood necks on most
    of my basses. Then you have to figure in "Q" or the resonant quality of
    the structure. Graphite serves to both increase stiffness, raising the
    pitch of any dead spots outside the primary range of fundamentals, as well as
    decrease "Q" or the severity of resonant spots where the neck sucks energy
    out of the string at a particular note.

    RE. the moving graphite necks. You'll notice that all examples cited have
    an unbalanced neck construction; by this I am referring to the use of
    phenolic fingerboards which have a different coefficient of expansion than
    does graphite. This is a classic recipe for a thermostat; it is a style
    of construction guaranteed to promote neck movement. Also, I believe the
    necks cited would come under the category of low efficiency use of
    graphite...lots of resin, a little bit of fiber. The way Modulus and
    Status manufacture their high performance (high fiber content, low resin
    content) graphite necks which conform to the patent I got in 1978 mitigates
    the problems of expansion and contraction. If manufacturers of "graphite"
    necks looked closer at aerospace-style construction, there would be no
    problem with this. The real way to go would be a monocoque, one piece
    molded hollow neck with not even a glue joint where the neck transitions into
    the fingerboard.

    the bit I'm particularly interested in is the possibilty of different materials (with different coefficients of expansion) for the neck and fingerboard causing the neck to bend due to temperature changes "a classic recipe for a thermostat".

    so for wood necks, would a maple/maple neck be more stable than a maple/rosewood or maple/ebony neck?

    or are the differences in the coefficients of expansion for these different woods too small to have any noticeable consequence?

    I suppose a maple/phenolic neck would have the stability of a bimetallic strip.....
  2. A non issue as far as most maple necks go. Very few have a separate fretboard of maple on a maple back - most are just one piece.

    As most of you know, I'm very opinionated in a lot of area's and this subject, while new to me, has gotten me to thinking. The question that is begging to be asked is how does a thin fretboard have such an effect on the much larger neck unit? At what ratio of the 2 different materials does this situation occur? I understand the principle of bi-metal thermostats. In that instance 2 dissimilar metals of equal dimension are used. But in a bass neck, there will always be large differences in the amount of material for the fretboard and the back of the neck. How is it that a relatively thin, relatively stable material like phenolic can make the larger massed neck move to the point of noticeable difference?
  3. pkr2


    Apr 28, 2000
    coastal N.C.
    I believe that if you have a neck and a fingerboard with widely varying enlongation rates caused by temperature variations, that you have an inherently
    unstable assembly.

    It's just a matter of degree.

    They (whoever "they" are :)) wouldn't really need a truss rod if it was a stable assembly.

    As long as there is a little tolerance in the set-up, it doesn't affect the playability all that much.

    There are basses with a maple FB and a maple neck. I own one.

    I notice No change at all with either temperature or humidity variations. It's always in tune when I pick it up.

    Believe it or not, there is not a dead spot on the neck.

    I give the credit to the same material being used for both the neck and the FB.

    YMMV! This is just one persons observations.:)

  4. I've got a maple/maple bass too (separate maple fretboard)- my Warmoth parts P bass.
    the neck is very stable- I've noticed no movement since building at the end of the year 2000.

    much more stable than my maple/ebony Fender P plus - then again this may be due to the sheer bulk of the warmoth neck in comparison to the slim fender one, and its twin steel reinforcing rods in comparison to the graphite rods I had put in the Fender.

    Sadowsky, Mike Lull, Ibanez (ATK) etc. all use separate maple fretboards- and so does Fender on their US standard and deluxe basses.

    I'd dare to guess that Musicman's method of constructing one-piece maple necks- slicing the fingerboard layer off, installing the trussrod then gluing it back, gives it the same properties as if the fingerboard was a separate piece to start with.
  5. This comes as news to me. Has Fender dropped the walnut skunk stripe in the maple boards? That was the reason for the thing in the first place - to put the trussrod in without having to put a seperate fretboard on top. If you've got a seperate fretboard, there isn't a reason to have trussrod slot in the back of the neck. My 76 P originally had a fretted maple one piece neck with skunk stripe and I replaced it with a '72 fretless maple that didn't have a seperate board either. I've got 4 other maple necks sitting in front of me now without seperate fretboards. I know that early Fenders (50's?) had a seperate fretboard but I've only handled a couple of those and thought that had pretty much gone away by the late 60's. I've also seen this on some of the cheaper knockoff's.

    Of course, with Warmoth, you have options for fretboards including birdseye maple which would make sense to have seperate pieces because of cost and cosmetics.
  6. i have the fender book of basses its has all the basses they made for production and ones i havnt seen but in the book.i need to find it ill look up about the finger board stuff tomore .
  7. Suburban


    Jan 15, 2001
    lower mid Sweden
    The temperature expansion coefficient varies quite signinficantly between different polymere materials, especially between well reinforced and less reinforced.
    The thermal differences between different spieces of wood is much less. This will probably never be of any significance.
    What could become an issue is the different humidity expansion factors. Some woods are almost stable, while others vary a lot! But, that is why they are oiled or laquered, to keep the humidity variantions away from the wood itself.

    So, differences in expansion coefficiences are not a problem in a well done wooden neckm.
  8. yep- remember that current US Fender Standard and Deluxe Jazz and Precision basses have graphite reinforcement rods in their necks-

    so these rods have to be inlaid into the neck as well as the truss rod- having to fit three skunk stripes would be impractical, so they're using separate maple fingerboards.

    Japanese and Mexican maple neck Fenders, and US reissues, don't have the graphite reinforcement, so the one-piece neck plus skunk stripe remains on those.
  9. bwbass


    May 6, 2002
    Our experience (at Warmoth) has been that our maple/maple necks are the most stable, and flame maple/ebony necks are the least stable. We attribute this to the difference in moisture absorption rates between the dissimilar woods.

    I don't see that a neck with a separate maple fingerboard should be any more or less stable than a one-piece maple neck, and of course the vintage truss rod in one-piece maple necks can have a detrimental effect on stability itself, because it puts the maple into lengthwise compression against the rod. The action of the truss rods in these necks is dependent on the dimensional stability of the maple.

    The exception would be when the neck is exposed to extreme heat stress, where the fingerboard's glue joint can slip and cause the neck to set into a bow.

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