Truss Rod technique - can I compensate for unequal curvature?

[dbarnes]

My tele's neck has unequal curvature - relief on the High E side is to spec, but on the Low E side is noticeably more pronounced. Tightening the truss rod seems to move the whole neck equally, so the two sides never show the same amount of relief.
Any tips on how to even things out?

[Jack Wells]

Sounds like you may have a twisted neck. A truss rod adjustment won't correct that. I had a little Mini Strat neck with a twist in it. I was able to remove most of the twist with clamps and time. You can test for a twisted neck by removing the neck and tuners and laying it on a flat surface. The back of the headstock and the heel should be on the same plane. If the neck rocks, it's twisted. You might be able to tell without removing the tuners by just sighting from heel to headstock.

I have a laminated piece of oak that's has an approximate 2 1/2 in. cross-section. I clamped the headstock to one end of it. At the other end of the neck I put shims (countertop laminate samples) under the low side and clamped the high side. The was done after removing the truss rod nut. Basically it's twisting the neck in the opposite direction and allowing time for the wood to take the twist. I'll try to get a picture of the set-up.

......

[chickenpicker]

Great photo, Jack.

I've used the same technique to untwist a much larger piece of wood - about 8" by 1" by 7' long. I left it over a weekend, not just twisted to "straight", but twisted beyond. When I released the clamps, it sprung back to straight.

[ftitele]

How much time did you actually give it to set?

[dbarnes]

jwells & chickenpicker,
Thanks for the advice (and the excellent photo!). I'll look into acquiring the clamps and a good straight block.

My tele is a recent acquisition for me, but it's 20 years old. When I bought it, it had relatively heavy strings on it (.011 + wound 3rd). It had been stored for several years, and my guess is that the strings were at tension. Luckily, the deformation is not severe.

Based on your experience, if I perform the clamping procedure will the neck stay straight for a good long time, or will it re-twist and require periodic re-clamping?

[Jack Wells]

I really can't say. I don't have that much experience with twisted necks. This one seems to have stayed pretty stable for the last couple of months. I should repeat ................. Make sure you remove the truss rod nut or at least loosen it a lot before you clamp it. It's always a good idea to take it out and lube the threads with soap or wax.

As far as time ........... that's hard to say. Hard maple probably takes a lot longer than other woods. Clamp it ...... let it sit for a few days ....... check it ......... re-clamp if necessary and repeat.

[jeffhigh]

How much difference is there in the relief between th low and high E.
It is not necessarily a bad thing to have a little more relief on the low strings to allow for their greater amplitude of vibration.
Does it play ok?
Depending on how much correction is needed, you might get away with a fret level or with leveling the board and refretting.
either of these would be more permanant than the clamping method (unless you use copious amounts of Heat)

[boris bubbanov]

dbarnes, once you've used Jack's great technique, may I suggest you keep the high E side of the neck fully tensioned while stored, with decreasing levels of tension over to the low E side where you have too much relief now?

I was impressed with how much variation in time to remove extra relief when I put a 1/4 clockwise turn into the truss rod of twenty or so necks; some responded as you watched, others took days to fully respond.

Good luck with that twist.


Bubbanov

[dbarnes]

An update - I spoke with two luthiers. Both agreed that with all string and truss-rod tension relaxed, the neck had taken on a permanent curvature. I then received two different proposals:
1. Don't try to flatten or recurve the neck. Instead, remove all frets and the nut, shave the fingerboard flat, then refret.
2. Do try to flatten the neck, using a steam press technique. This leaves the original frets in place, but they'll require redressing.

Cost of the two operations was about equal. I opted for #2 because it doesn't require removing fretboard wood. Also, the curvature of the neck was significant enough that in some places the fretboard would have been very thin when the operation was complete.

The luthier who offers the steam press technique has used it many times to restore Martin guitars which (I didn't know this!) did *not* have steel truss rods until the '70s.

So it's in the shop now -- we'll see what happens.

[mellecaster]

"The luthier who offers the steam press technique has used it many times to restore Martin guitars which (I didn't know this!) did *not* have steel truss rods until the '70s."

Well I'm afraid your luthier is mistaken on that...Martins had Steel channel non-adjustable bars in their Necks for years....well up until the early 80s....and then changed to the more conventional adjustable truss rod, that is offered now..just to set the record straight.....

[Daddydex]

I have found that clamping only works temporarily. At least that is my experience with a Jazz bass I have been trying to fix. I have clamped it twice so far and after a week or so it bends right back. The second time I clamped it for a whole week but it still didn't hold.

Dan

[dbarnes]

Originally Posted by Daddydex

I have found that clamping only works temporarily.

Yeah, I'm concerned about that. I'm trying this process for two reasons:
(1) Maybe the addition of steam will force the wood to "reset its memory" so the cure will stick, and (2) if it doesn't work, the "shave the fingerboard" option is still available. If I can afford to keep doing this, that is.

[dbarnes]

Originally Posted by mellecaster

...Martins had Steel channel non-adjustable bars in their Necks for years....

Big sigh of relief, here. Everything I thought I knew about steel string guitars was going up in smoke -- I couldn't imagine how Martins could be such great-sounding, long-lasting instruments without some steel in their necks.

I found a website that shows some of the old truss rods -- it's like that BodyWorks exhibit that's touring the country -- try not to think about where these came from or what had to be destroyed to reveal them:

http://www.fretnotguitarrepair.com/M...Truss_Rods.htm

The author acknowledges that many Martin owners believe they have no truss rod because there's no external adjustment. Interesting that a factory-authorized luthier would also be under that impression. I know he does excellent work, though...plenty of testimonials from trusted sources.

[ramblinmike]

what is the best way to prevent a neck from twisting? or is it just a matter of luck? I leave my guitars in the cases with the strings in tune and the truss rods at the same tightness they are when they're being played, should I be doing something different?

[Vizcaster]

Originally Posted by boris bubbanov

I was impressed with how much variation in time to remove extra relief when I put a 1/4 clockwise turn into the truss rod of twenty or so necks; some responded as you watched, others took days to fully respond.

I just did a level/crown/and polish on two new Musikraft one-piece maple necks that were basically straight out of the box (actually there was a touch of backbow on one so I straightened it before leveling the frets). Now that they're lacquered and strung up, backing off a little less than a quarter of a turn took them from .005 to .008, but after two days they're measuring more like .010 (using a straightedge, I think if I used the strings to measure I'd be estimating it at .012).

Boris, do you think they would have started to show some relief even if I never loosened the rods, in other words they are just settling in under string tension - or would you say that the adjustment I made took this long to kick in?

[chickenpicker]

Originally Posted by ramblinmike

what is the best way to prevent a neck from twisting? or is it just a matter of luck? I leave my guitars in the cases with the strings in tune and the truss rods at the same tightness they are when they're being played, should I be doing something different?

If a neck's going to twist, it's going to twist.

[blacklinefish]

Originally Posted by chickenpicker

If a neck's going to twist, it's going to twist.

Hah, that reminds me of a luthier's comment about my 1979 Les Paul. The neck had a dip, a hump, a 16th-fret spatula, and a slight twist. He held it up, sighting down it and muttered to himself "yeah, that's a Gibson neck alright." I drummed up the courage to ask him if this was due to my storage or treatment of the guitar. He told me that he could probably guarantee that it left Nashville in that exact shape and that its two owners (incl. me) had just compensated with high string action.

He fixed it and it is perfect now.

--gh

[dbarnes]

Originally Posted by ramblinmike

what is the best way to prevent a neck from twisting? or is it just a matter of luck? I leave my guitars in the cases with the strings in tune and the truss rods at the same tightness they are when they're being played, should I be doing something different?

Both luthiers I talked to agreed that there's no "adjustment" for twist. With my Tele, which was stored for six or seven years with heavy strings at tension, the permanent bow could have been reduced or eliminated if the truss rod had been tweaked when the problem first appeared. But the owner wasn't playing the guitar, so the problem went unnoticed.

Conclusion: I think if you're simply paying some attention to your guitars, you'll be able to ward off many of these troubles.

[dbarnes]

The tele's back from the shop with a straight neck, new bone nut, and dressed frets. Plays great!

The luthier did a great job for me, so I owe it to him to set the record straight:

Originally Posted by mellecaster

"The luthier who offers the steam press technique has used it many times to restore Martin guitars which (I didn't know this!) did *not* have steel truss rods until the '70s."

Well I'm afraid your luthier is mistaken on that...Martins had Steel channel non-adjustable bars in their Necks for years....well up until the early 80s....and then changed to the more conventional adjustable truss rod, that is offered now..just to set the record straight.....

Mellecaster's right, of course.
Turns out the luthier was well aware of the non-adjustable bars. To him, "truss rod" implies "adjustable," so I misunderstood him. Apologies.