truss rod for short scale (20.75")

Discussion in 'Tele Home Depot' started by Dimitree, Jun 30, 2020 at 5:05 PM.

  1. Dimitree

    Dimitree Tele-Meister

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    I'm going to build a really short scale (20.75"), sorta like John Lennon's Rickenbacker 325, but mine will be 12 strings.
    I'm wondering if the truss rod that Stewmac sells, the Hot Rod dual action will be good for it. I would choose the 14-1/4" length. Probably not long enough, but what do you think?
    This is a projection of how it would be placed.
    The center of the rod would be under the 7th fret. Is that ok?
    The construction will be neck-through
     

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  2. guitarbuilder

    guitarbuilder Telefied Ad Free Member

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    You can move the brass anchor block farther back under the fretboard between the nut and fret 1 , and that's what I'd do. It'll go back to the 20th fret or so with the adjustment nut right at the opening under the nut. That way your adjustment slot doesn't need to be super long as it would be now. You are spanning the heel to nut and that should work fine. You could also add a carbon graphite strip on each side of the rod too if you really wanted to be stiffer.

    https://www.stewmac.com/luthier-too...MIvba6j8Cq6gIVB5yzCh3eMgD1EAQYBSABEgI_j_D_BwE
     
    Last edited: Jun 30, 2020 at 5:40 PM
  3. Mr_Q

    Mr_Q Tele-Meister

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    Marty's direction seems sound.

    I'm no expert, but the other thing I've done to stiffen a neck is laminate two or three pieces of wood with the grain alternating direction. Of course, that may not be consistent with your design intent. YMMV.

    ~Q
     
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  4. Dimitree

    Dimitree Tele-Meister

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    Thanks! The neck will be indeed laminated, I’ve done some neck this way and they indeed are stiffer. But my concern was not about the stifness, but about the functionality of the rod in that position
     
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  5. Freeman Keller

    Freeman Keller Friend of Leo's

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    LMII sells 12, 13-1/4, 14-1/2, 17 inch double acting and several short single acting (old Martin style). I've been very happy with their rods. BitterRoot will make any length you want.

    Your drawing is perfect, the neck is inert from the heel on. The t/r could be a hair longer but that will work.

    Ps - think carefully about your string gauges and tunings, do the calcs for the short scale.
     
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  6. crazydave911

    crazydave911 Poster Extraordinaire

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    I've essentially doing the same thing but only a slightly longer scale, 23 25. I walk to the beat of a different drummer,ask anybody lol. My solution was a reinforcing rod. 1/4" cold rolled steel courtesy McMaster & Carr. It extends to 1/2" of the heel and nut,epoxied in. This has the advantage of no air gap under the fretboard. If it matters CF Martin did this over 40 years :)

    Dave
     
  7. Dimitree

    Dimitree Tele-Meister

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    thank you everyone! I'm routing the channel right now and will install a little bit down towards the body than as shown in the first drawing.

    do you think it's still possible to do a short scale 12 strings? I had some doubts at the beginning since I never saw one, but then I said, why not..after all I already have enough "standard" guitars, I don't need another one
     
  8. Freeman Keller

    Freeman Keller Friend of Leo's

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    OK, I just did some playing with the string tension calculator at D'Addario's site.

    Lets start with a common electric twelve string set - EXL150's. On a 25.5 scale guitar at concert pitch they exert about 214 pounds (I know I should do this in metric for you but I'm lazy). If I drop the scale to 24.0 (about the same as a JagStang) the tension drops to 189, still reasonable. Going to 20.75 the total tension is 141 pounds.

    While this is significantly more than a six string electric with 10s if you look at the individual strings one is below 10 pounds and several are right at ten pounds - that is a recipe for buzzes.

    There are a couple of options - first you can tune up a few semi tones. Running the calculator again it looks like tuning to G (three steps up) will get you close. The other option is to increase you string gauges - going up to 12 - 56 at concert again gets you close.

    So, not saying it won't work but in my humble opinion the feel will be pretty flabby. I go the other way with my twelve strings - longer scales, fatter strings and tuned in the cellar.

    One option if you have access to a twelve string electric would be to tune down three semi tones (C#) and put a capo on the third fret. You are back to standard tuning but with the greatly reduced tension - see what you think.
     
    Last edited: Jul 4, 2020 at 6:48 PM
  9. Freeman Keller

    Freeman Keller Friend of Leo's

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    There is one other option, build something like this

    http://www.veilletteguitars.com/acoustic_gryphon.shtml

    The interesting thing is its tuned to a D (10th fret of a normal guitar) with fairly normal strings. It is, however, tuned totally in unison - I'm not sure what octaves would sound like.
     
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