Advanced Truss Rod Adjusting

Discussion in 'Project Depot' started by Manodano, Aug 30, 2019.

  1. Manodano

    Manodano Well-Known Member Supporting Member

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    I grabbed a late seventies Yamaha FG-140 dreadnought-sized flat top at a yard sale last week. All original, apparently including the strings. Sunburst laminated spruce top, mahogany back, sides, and neck. Hardly played, but a good number of dings, pretty beat up, and generally unloved all of its life.

    I bought the guitar from friends that date back to high school days. Their late dad was a prominent music business lawyer, Horton Frank. The story goes that Ricky Van Shelton gave Horton Frank the guitar to keep in his law office so that Mr. Frank's various artist and songwriter clients could play him new material when they came to the office. The daughter said Mr. Frank had no interest in guitar, and that the instrument stayed in the corner of his office for a couple of decades. Pics to follow.

    I picked up and laid down the guitar several times, and even left the sale for an hour and then decided to go back to get it. The 70's, made in Japan, Nippon Gakki label FG-Series Yamaha guitars are known to to play and sound pretty good. I thought this one sounded real good even in its unloved state. The action was a little on the stiff side, and I knew the 40-plus year old guitar would need a truss rod adjustment. No biggie.

    Long story short, through the miracle of the internet, I found a great Yamaha FG Series enthusiasts site. Here's a post showing how best to adjust the truss rod:
    http://yamahavintagefg.com/how-to-properly-adjust-the-truss-rod/

    Sure enough, the truss rod won't tighten the sturdy 40 year-old mahogany neck, so I'm either going to make a "Back Bowing Block" and pre-bow the neck myself as per the link, or take the guitar to a tech and let him do it. Man, it kills me to take a $100 yard sale guitar to a tech, but I think this one might be worth it.

    Anybody have any experience with such a thing, or have any advice to offer? I would like opinions on what the probability of me being able to properly do this myself are.

    I think I can.
     
    Last edited: Aug 30, 2019
  2. Manodano

    Manodano Well-Known Member Supporting Member

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    I think I can.

    Yeah, yeah, pics to follow.

    Bump
     
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  3. tonray

    tonray Well-Known Member Supporting Member+

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    A guitar that just sat under constant tension for 40+ years without any attention may need a neck reset to fully restore playable action.
     
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  4. artandsoul

    artandsoul Well-Known Member

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    if the truss rod isnt enough to make the back bow right its common to use some washers to take up the slack the get more tension on it. if that doesnt work i have let the rod go loose and clamp the neck down with a ton of relief and let it sit a few days to hope it gets strait. that link says set it tuned to pitch, i say no, loosen it up before u put the tension on it.it only takes a day or so. I have even used a heat gun to speed up the bow if its that severe. ill say good luck it can be a pain in ash or easily fixed with washers on the truss rod. or clamped down with a normal clamp and a heat gun to persuade it to move if its that severe. im sure someone here has better experience with vintage truss rod issues than me but it can be fixed ive fixed a few bananna basses with heatgun and clamp overnight to be playable
     
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  5. idiotsdelight

    idiotsdelight Well-Known Member

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    I have 4-5 of those 70's Yamaha FG's. My black label 160 is my favorite. Big neck.
    Also a 110, a 110E, a 330, also had a 75 which I really regret selling. Might have another. When I see them for cheap I buy them.

    I just played a reset neck FG red label 12 string a week ago. It was killer. When I go back over I'm gonna need to call dibs on that thing.

    If it's a severe bow you might need to remove the fretboard to get the neck back.
     
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  6. Manodano

    Manodano Well-Known Member Supporting Member

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    I don't think the neck bow is severe, but the guitar could play a lot better with a little more "hump". But it has sat for 40+ years unloved and un-adjusted, and the neck wood is aged, dense and rigid, and doesn't have any "give".

    Musing over these replies, I'm thinking maybe I'll start by tuning the guitar to pitch, and using my straightedge to see exactly what my baseline condition measures at a couple of spots. Then I'll remove the strings, let it sit a day or so, and again use my straightedge to gauge whether the neck moved or not. Then I will fully loosen the truss rod, let it sit a few days, and again see how much the neck moves. Then I'm going to clamp it to straight, maybe a hair past straight, using the straightedge to gauge where "straight" actually is. I can leave this clamped for several days if need be.

    I need some direction on how to apply the heat, which is what this job warrants. What temp, and where?

    I have an old two-setting heat gun, about worn out, and a new-ish hair dryer that blows pretty hot. I don't mind buying a new heat gun if need be, I've had my eye on one anyway.
     
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  7. Mickey

    Mickey Gandalf the Intonationer

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    Did ya ever stop to think there are people who would pay a few cubic dollars for that guitar because it was once owned by Ricky Van Shelton?
    George Gruhn once told me that rule of thumb celebrity connection adds $5000 to the value of a guitar, except for a few (Hank Willians? Elvis?) adds $10,000.
     
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  8. MichaelR

    MichaelR Well-Known Member Supporting Member

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    I would be very careful with a heatgun myself, I think taking your time like you are about to do should be enough. If you need heat there's this thing called the sun that will do the trick.
     
  9. backinit

    backinit Well-Known Member

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    So the neck needs to be preflexed in order to be tightened? I would definitely try to get a stainless steel washer under that truss rod nut. Maybe while it's under tension if the block submit it to a higher mousture environment such as a bathroom with a hot shower going.
     
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  10. Manodano

    Manodano Well-Known Member Supporting Member

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    I forgot to tell you that, actually, Elvis gave the guitar to Hank Jr., who gave it to Ricky, who then gave it to Mr. Frank. Before any of that happened, George Jones played the guitar on "She Stopped Loving Her Today" with Keith Richards listening from the control room. Vince Gill walked up and asked about the guitar while I was paying for it. He wanted to give the guitar to Amy as an anniversary gift, but I told him he and Tim McGraw together didn't have enough money to get me to part with it.

    This is my version of gambling - I admit I get a kick out of taking chances on orphaned guitars. They've tried to get me some help, but I've eluded the cure so far. And dangit, I hadn't been to a good yard sale all summer! At least I kicked my weakness for pathological lying!

    P.S. I bought the clamp I needed today. I hope in the next few days to make up my wooden block and get clamping.

    Pics to follow, I promise.
     
    Last edited: Sep 1, 2019
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  11. jwguitar

    jwguitar Well-Known Member

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    Unless the guitar has a lot of meaning to you (which it sounds like it does) I would just leave it be since a neck reset is a big expense. However, I can certainly understand your thinking on this one.
     
  12. andrewsrea

    andrewsrea Well-Known Member

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    I remember seeing some good videos on Stew Mac's website.

    I used steam and a weight, with the guitar strapped to a ping-pong table once. The right repair would have been to remove the fret board and fix the truss rod.
     
  13. Manodano

    Manodano Well-Known Member Supporting Member

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    Well, I finally got some pics, including my clamp job.

    I got a good fix on the bow, and it really wasn't all that bad, and it was centered around the 4th fret, not in some other wonky spot. So, I completely loosened the truss rod, clamped the neck, and created a very slight hump right around the 4th fret. Then I left it alone. I'm going to let it sit for a while, then I plan to tighten the truss rod while the clamp is still in place, and see what happens when I remove the clamp.

    My guitar is a sunburst, I don't know if that is rare or not:

    IMG_2401.JPG
    The swirls in this pic are just reflections - the mahogany back looks pretty good:
    IMG_2403.JPG


    The headstock has some nasty dinks. There might have been some drankin' going on down there on Music Row and the guitar got kicked over a time or ten. The guitar has the original metal "Yamaha" truss rod cover and all three screws, but it's off in this picture:
    IMG_2402.JPG
    Here's my clamping block setup. No big deal, after all. But man, I was CAREFUL not to crank it too tight. As my old luthier pal Jed Clampit used to say, "I jest barely created a leetle hump to offset the untensioned bow - wheee doggies." I used wood scraps that I had handy. I got the clamp at Home Depot for around $15. It's an 8" clamp which I thought would be way too big, but the 6" clamp would not have done the job, for sure. I cut a piece of foam from an old, thick mouse pad that I saved in my "craft" drawer and put that between the clamp and neck to protect the neck.

    This is going to sit for a while:

    IMG_2404.JPG

    Maybe its going to work.
     
    Last edited: Sep 3, 2019
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  14. Manodano

    Manodano Well-Known Member Supporting Member

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    So, after letting Jed Clampit sit for a day and a half or so, I left the clamp under tension and removed the truss rod adjusting nut, and used it to eyeball the diameter of the rod, and the diameter of the recessed hole in the end of the neck that the adjusting nut disappears into as it's tightened.

    Then I scrounged a couple of washers that fit on the rod, and also into the hole, from my hardware bin (that took some work, these washers are tiny!). I slid the washers onto the rod and down into the hole, as per backinit's helpful suggestion. Looking at the headstock picture previously posted, you can see that there was hardly enough of the nut exposed to tighten the rod any further. I knew inserting one or two washers was warranted. Here's what I used for a washer, and I had to drive a punch in them to open them up so they would fit. I used two of these tiny things:
    IMG_2405.JPG

    Then I tightened the truss rod as tight as I thought prudent, and then released the clamp and strung up the guitar. There was some very underwhelming improvement - and still more bow than I could live with.

    So, I removed the strings, and I clamped the neck again. This time I moved the clamp from under the fifth fret to under the seventh fret. I also used a little less caution when tightening the clamp - I wanted to see that hump!

    I let that sit for about four hours, then I swallowed hard and was able to tighten the truss rod about two more full turns.

    When I released the clamp the second time, the neck retained a slight hump. Looking good! When I restrung the guitar and tuned it to pitch, I now had just a little too much hump - and I declared the victory! The G string was buzzing at the first fret, and the high E string was buzzing at the sixth fret. So, I carefully loosened the rod in tiny increments unto the buzzes went away.

    The action is still a little on the high side, but I'm in the ballpark of maybe getting lighter gauge strings, or possibly fooling around with the nut and saddle heights to tweak the action. The guitar sounds real good to my ears, and I'll keep tweaking it.

    Here's a picture showing the rig I used to adjust the truss rod adjusting nut, and the original metal truss rod cover. The tool is a 5/16 nutdriver socket with a 1/4" wrench on the shaft. The red tape simply prevents the wrench from sliding down the shaft and getting all wedged into the tight headstock rout. It's an awkward rig, and barely all fit in the rout, but it worked out great:

    IMG_2406.JPG
     
    Last edited: Sep 3, 2019
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  15. backinit

    backinit Well-Known Member

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    I declare this is a victory!
     
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  16. Manodano

    Manodano Well-Known Member Supporting Member

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    Remarkable 24 Hour Update:

    I had to go to the basement this morning, and I picked up the guitar for a quick second and was amazed to find that the neck clearly settled more overnight, and in a good way. The action improved on its own. The string height was visibly more consistent from the nut to the heel end of the neck. I was expecting buzzes and fret-outs and maybe a need to loosen the rod, but there is no buzzing anywhere. This is somewhat due to dumb luck!

    So, what I saw was that it took about 18 hours hours for the tightened truss rod to actually fully deflect the neck.

    Who knows what kind of results a patient man might get doing this!

    I played the guitar at length tonight, and I'm really happy with the results and appreciate all the advice.
     
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