Truss Rod Tweek

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West R Lee

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Backed off the truss rod nut about a 1/4 turn last night on the D25. She's got just a hint of an inward bow with a bit too much clearance at the 12th fret, and a subtle bow towards the 3rd fret which can be seen looking down the neck. She's become my guinea pig guitar, we'll see how it goes. It's been 12 hours.

West
 
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JazzyDaddy

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West,

How did it turn out?

I don't think my '76 D-25 has ever had the truss rod adjusted. The action seems fine; fairly low across the neck. No buzzing.

Dave
 
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West R Lee

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Jazzy,

I know this isn't what you want to hear, but it's hard for me to say. Let me explain.

My D25 is a beautiful guitar without a doubt, Guildmark (very talented and knowledgeable) has played her a couple of times, and he likes her. The finish on her is almost mint, but as a child, I abused her. When I was in my early 20's, I'd go on these weekend long camping trips during the summers, and do really stupid things, like leave her in a tent, trunk of a car, etc. In Texas, summer days often exceed 100 degress, and in the trunk of a car? Now, at 50 I shudder to think. Anyway, she's had a bit of bridge pull from the bottom for over 25 years, it's never moved mind you, but it does raise the action. Some say that extreme heat will loosen the glue in the neckblock and it will never be right without a neck reset. I don't know enough about guitar repair to comment about that, but it certainly makes sense to me. Needless to say, to me, the action is a touch high, and if you look down the neck from the top, you can make out an ever so slight bend around the 3rd fret. That's why I tweeked the neck, in an effort to get that bit of bend out, and hope the action was lowered a tad in the process. She's still got plenty of saddle, so I can go that route if I choose.

As far as results? If there are any from my very, very slight loosening of the nut, I don't see any. Maybe someone with a keener ear and eye might, but I'm half deaf and blind. My D25 has the most sentimental value, being my first and only new Guild, but it's the least valuable monetarily speaking, so she's my guinea pig.

West
 
GardMan

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West... I may have gotten this absolutely backwards (I get easily confused), but I think loosening the truss will have the opposite effect from what you wanted. Loosening the truss relaxes the neck, lets the strings pull it into a forward bow, and would tend to raise the action (increase the relief). Tightening the truss counteracts the pull of the strings, causing the neck to straigthen or bend back (decrease the relief). Or am I backwards on this, again? Dave
 
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West R Lee

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:lol: Yep, I remember the thread now, man this getting old is tough. If you don't mind, one more time Gard. This shouldn't be confusing. I suppose if I had a clearer visual picture of the function of the truss rod, it might not be so confusing, and to think I reapir multimillion dollar equipment for a living, doesn't belong to me so that makes it easier. I don't pay for booboos at work either!

OK, as you looked down my fretboard from the top towards the headstock, there was or is a very slight bow OUT, like sting tension had pulled it there. My thinking was that the truss rod is anchored or threaded into something in the neckblock and loosening the nut, counterclockwise would lengthen the rod so to speak forcing the neck to be pushed back toward straight or allowed/forced to bend backward, and that force or bending would make the arion closer up the neck. Does that make sense? Am I bassackward here?

West
 
GardMan

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West,
First, let's make sure we're on the same page regarding directions. While looking at the truss-rod nut (so in a headstock to heel direction), CCW loosens ("lefty loosy") CW tightens ("righty tighty").

I think your analogy is the same view that made me get it backwards in the thread last July. However, the truss is only anchored at one end... the nut doesn't anchor to the neck, so loosening it (CCW turn while looking at the nut) can't actively extend the rod or neck.

I think the correct view is to view the strings and truss applying tension to opposite sides of the fretboard (which is thus under compression). If you increase string tension or decrease truss tension (loosen the truss nut), the fretboard bends forward (increasing relief). Alternately, if you decrease string tension (lighter gauge strings or tune down) or tighten the truss rod nut, the fretboard bends backwards (decreasing relief).

I have had a little more experience since we last discussed it in July... my D-46 came with med or heavy strings on it. When I switched to lights, the neck backbowed. I loosened the truss 1/4 turn at a time (took 1/2-3/4 turn eventually) until the relief was acceptable and the buzz disappeared... basically, I released tension on the truss, until the lighter gauge strings pulled the neck forward to where I wanted it.

I just hope I am getting this right this time, but I think I am.
Dave

Edit: One more tip: I mark one face of the truss nut... usually the one closest to "up" in the slot... with a "sharpie" (marker), so I can remember where it was when I started. That way, I can always get the neck back to my starting point, before I started messing with it. Hope this helps... or that someone will come and tell me that I got it bass-ackwards (again). Signing off! D
 
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clark bjorke

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Confirming what others have said, your truss rod works under tension, not compression, to counter the effect of string pull. Tightening the nut will take the bow out of the neck. If there are other issues, such as top bulge or bridge movement, those should be addressed at the bridge and/or, in an extreme case, by a neck reset. If the bridge has not pulled off the top but you see a bulge in the top you may be able to compensate by lowering the saddle. In the meantime carefully tighten the truss rod nut a quarter turn at a time, with the strings loosened. I like to re-tune and leave overnight to allow it to settle in after each 1/4 turn, before checking my progress.

I don't think my F-30 had a truss rod adjustment in all of it's 44 years of existence until I took it home. The nut was at the very tip of the rod. It reminded me of my first Sears Silvertone for playability.
 
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cjd-player

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West, to measure the effect of the truss rod adjustment (relief) put a capo at the first fret. Then fret the string being measured at the 12th fret. While it is fretted, measure the string height above the 5th fret (some prefer using the 6th fret) using feeler gages. Typically the measurents are done on the first and sixth strings to give a number to the relief setting.

That will give you a real measurement in thousandths of an inch (I know that's familiar territory for you), and you can measure the effect of the truss rod adjustment as you increase or decrease relief.
 
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clark bjorke

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cjd-player said:
West, to measure the effect of the truss rod adjustment (relief) put a capo at the first fret. Then fret the string being measured at the 12th fret. While it is fretted, measure the string height above the 5th fret (some prefer using the 6th fret) using feeler gages. Typically the measurents are done on the first and sixth strings to give a number to the relief setting.

That will give you a real measurement in thousandths of an inch (I know that's familiar territory for you), and you can measure the effect of the truss rod adjustment as you increase or decrease relief.
Click to expand...


Measurements? How quaint!
 
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