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4-string truss rod.

Posted by Kel Wilson on February 1, 2011 at 6:25pm in Building Secrets, Tips, Advice, Discussion

So many threads mentioning this subject I couldnt decide where to post.  Decided to just ask.

 

My current (second build) build is a 4-string, with a 1x2 poplar neck with a red oak fret board that will be glued down.

 

This string set, https://www.cbgitty.com/cubecart/strings/acoustic-medium-4-string-cigar-box-guitar-strings-open-g/standard-tuning/prod_91.html

 

I'm pretty sure I wont need an adjustable truss rod, but contemplating a steel or aluminum rod just for strength...

 

Thoughts?  Help?

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Replies

  • Leroy Beal February 3, 2011 at 1:44am

    I use the 1/8" x 3/8" flat bar. I use a table saw to cut the slots early on in the neck building process. The correct blade makes a nice snug fit. Wood glues makes a permanent install. I get it from LMII or StewMac. A truss rod just weakens a neck.

    http://www.stewmac.com/shop/Truss_rods/Carbon_fiber/Carbon_Fiber_Ne...


    Glaze said:

    Leroy

     

    Awesome looking baritone.  What size of carbon fiber are you using and where are you getting it?  

     

    I have some carbon fiber that is 1/4" x 1/4" square by 26" long and it is very strong and stiff, but I would recommend a bigger size for a full scale length six string guitar neck.    

     

    A friend of mine has a Vigier electric and those guitars have a wood neck with carbon fiber reinforcement only without a truss rod.  My friend told me the neck stays flat on his and it  works great, so it can be done with carbon fiber.  I think the key is using the right sized quality carbon fiber bar and using enough of it.    

    Leroy Beal said:

    On my last 6 regular guitar builds, (6 string acoustics and electrics, 8 string acoustic baritone, and a 12 string electric) I have used only carbon fiber flat bar reinforcements. No truss rods. I use 2 or 3 bars depending on how many strings on the instrument. They have all been strung to concert tuning from one month to one year. None have shown any sign of movement or twisting. All are as straight and solid as the day I finished building them.

     

    baritone8stringoctar03.jpg

    I just measured the relief on my 8 string acoustic baritone, which has tremendous string tension, and it measured only 1 mm after a year. That is good enough for me. If people are having problems, then they are not building it correctly.

     

     

     

     

  • Kel Wilson February 2, 2011 at 8:02pm

    Thanks for the advice fellas. 

    I was almost finished with the neck when my concerns popped up..so manking ne from a stronger wood wasnt on my list to do.

    opted for the steel bar in this one.  Where might I find the carbon fiber rods for future use?

     

     

    Now I just need to decide on a tail piece. heh

  • Glaze February 2, 2011 at 1:24pm

    Leroy

     

    Awesome looking baritone.  What size of carbon fiber are you using and where are you getting it?  

     

    I have some carbon fiber that is 1/4" x 1/4" square by 26" long and it is very strong and stiff, but I would recommend a bigger size for a full scale length six string guitar neck.    

     

    A friend of mine has a Vigier electric and those guitars have a wood neck with carbon fiber reinforcement only without a truss rod.  My friend told me the neck stays flat on his and it  works great, so it can be done with carbon fiber.  I think the key is using the right sized quality carbon fiber bar and using enough of it.    

    Leroy Beal said:

    On my last 6 regular guitar builds, (6 string acoustics and electrics, 8 string acoustic baritone, and a 12 string electric) I have used only carbon fiber flat bar reinforcements. No truss rods. I use 2 or 3 bars depending on how many strings on the instrument. They have all been strung to concert tuning from one month to one year. None have shown any sign of movement or twisting. All are as straight and solid as the day I finished building them.

     

    baritone8stringoctar03.jpg

    I just measured the relief on my 8 string acoustic baritone, which has tremendous string tension, and it measured only 1 mm after a year. That is good enough for me. If people are having problems, then they are not building it correctly.

     

     

     

     

  • Leroy Beal February 2, 2011 at 11:56am

    On my last 6 regular guitar builds, (6 string acoustics and electrics, 8 string acoustic baritone, and a 12 string electric) I have used only carbon fiber flat bar reinforcements. No truss rods. I use 2 or 3 bars depending on how many strings on the instrument. They have all been strung to concert tuning from one month to one year. None have shown any sign of movement or twisting. All are as straight and solid as the day I finished building them.

     

    baritone8stringoctar03.jpg

    I just measured the relief on my 8 string acoustic baritone, which has tremendous string tension, and it measured only 1 mm after a year. That is good enough for me. If people are having problems, then they are not building it correctly.

     

     

     

     

  • Wade February 2, 2011 at 11:50am

    Don't think you need a truss rod if you find a good piece of poplar and oak - But all wood does not have the same strength. Look for stuff that has a tight grain and  as close to quarter sawn as possible. Never had a problem when doing this. Shorter scale and tuning will also play a huge part in deciding if you need to have a truss rod.

    Good Luck with you build,

     

    Wade

  • Glaze February 2, 2011 at 11:12am

    Kel

     

    There is a guy on You Tube that built a four string cigar Harley Box.  The tone he got out of it was incredible.  He mentioned that the neck on his build would move too much under different tunings under the posts on his vid.  

     

    I have been thinking about this exact thing for two weeks.  I have some quarter sawn hard rock maple that I though I would use for a three stringer neck, but how to keep it straight?  I thought I could make the neck wider and thicker than most guy's build them on here to make the neck resist the string pressure.  I could put a 3/8" square cold rolled steel bar in the neck and that should keep it flat, but it would be heavy.  Some larger pieces of carbon fiber in the neck could work, but I asked some acoustic guitar builders I know who tried carbon fiber only without a truss rod and they said the neck moved too much on their builds.  Carbon fiber is stronger than steel by weight meaning you have to use enough carbon fiber to equal the weight of steel to be as strong.  

     

    The single action truss rod works great and it's light.  I like the look of the Martin style truss rod that Stu Mac sells, but I have never installed one.  Should work great though.        

  • Wes "I'm Baaaaack" Yates February 2, 2011 at 7:04am
    I have put a 1/2"x1/8" steel bar from home depot or lowes in necks. Put them in vertical (perpendicular to the fretboard) and glue it down. Make a channel 9/16" deep. Works great. Take a lok at my picks.

    -WY
  • BT Cohosh February 1, 2011 at 6:28pm
    You could probably go either way.  The last 2 four-strings I've built I've put a steel bar under the fret board just to make myself feel better.  I don't know whether or not it's actually doing anything.
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