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Minor upbow / maxed out rod
https://www.luthiersforum.com/forum/viewtopic.php?f=10137&t=54761
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Author:  joshnothing [ Wed Feb 09, 2022 6:47 am ]
Post subject:  Minor upbow / maxed out rod

Got a strat in for a fret level to deal with the usual ski ramp issues.

Upon examination, the neck is exhibiting a little more upbow than the truss rod can handle. Under string tension relief is at .007” with the rod maxed. Without string tension the neck goes just barely into backbow with the rod set like this. Backing the rod off a tiny fraction (like 1/12th turn) gets the neck straight, loosening it any more sees it go into pretty major upbow.

I don’t really want to level the frets with the neck straight as string tension will pull more relief into the neck than the tiny remaining adjustment range of the rod can correct.

Would it be acceptable to loosen the rod a little more and level out some of the excessive upbow with the aim of hitting lower relief under string tension and having slightly more scope for rod adjustment?

Author:  Chris Pile [ Wed Feb 09, 2022 9:08 am ]
Post subject:  Re: Minor upbow / maxed out rod

Does the truss rod have smooth travel in each direction? Some necks will relax after tightening the truss rod all the way and leaving it for a day or two, and then loosening it all the way for a day or two. A couple back and forths (provided you have the time) can works the kinks out of the neck - so to speak.

Author:  Barry Daniels [ Wed Feb 09, 2022 9:26 am ]
Post subject:  Re: Minor upbow / maxed out rod

Some truss rods max out because you hit the end of the threads. A thick washer under the nut may give you several more turns.

Author:  joshnothing [ Wed Feb 09, 2022 3:09 pm ]
Post subject:  Re: Minor upbow / maxed out rod

Chris Pile wrote:
Does the truss rod have smooth travel in each direction? Some necks will relax after tightening the truss rod all the way and leaving it for a day or two, and then loosening it all the way for a day or two. A couple back and forths (provided you have the time) can works the kinks out of the neck - so to speak.

Travel is smooth but short - less than a half turn from loose to tight, and the same going the other way (two-way rod). Great tip, I’ll give it a try.

Author:  joshnothing [ Wed Feb 09, 2022 3:51 pm ]
Post subject:  Re: Minor upbow / maxed out rod

Barry Daniels wrote:
Some truss rods max out because you hit the end of the threads. A thick washer under the nut may give you several more turns.

Thanks Barry, great idea. It’s a bi-flex so I’ll try to remove the little walnut plug and take a look.

Author:  SteveSmith [ Wed Feb 09, 2022 6:24 pm ]
Post subject:  Re: Minor upbow / maxed out rod

I use a soldering iron with a temp control to heat up the walnut plug and they come out pretty easy.

Author:  Hesh [ Thu Feb 10, 2022 4:14 am ]
Post subject:  Re: Minor upbow / maxed out rod

joshnothing wrote:
Got a strat in for a fret level to deal with the usual ski ramp issues.

Upon examination, the neck is exhibiting a little more upbow than the truss rod can handle. Under string tension relief is at .007” with the rod maxed. Without string tension the neck goes just barely into backbow with the rod set like this. Backing the rod off a tiny fraction (like 1/12th turn) gets the neck straight, loosening it any more sees it go into pretty major upbow.

I don’t really want to level the frets with the neck straight as string tension will pull more relief into the neck than the tiny remaining adjustment range of the rod can correct.

Would it be acceptable to loosen the rod a little more and level out some of the excessive upbow with the aim of hitting lower relief under string tension and having slightly more scope for rod adjustment?


If the rod is maxed out after the washer thing see below:

Yep you've got it. You can reshape the fret plane and this one needs it too. I would relax the rod, encourage the forward bow and then mill it out. Are the frets tall ones from a more modern start if so you are good to go. This could be done as a refret too and some of the frets by the nut will get pretty low.

Author:  Burton LeGeyt [ Thu Feb 10, 2022 2:25 pm ]
Post subject:  Re: Minor upbow / maxed out rod

I've been loving the new (ish) Stew mac understring levelers for stuff like this.

https://www.stewmac.com/luthier-tools-a ... g-leveler/

Instead of using the truss rod to adjust the neck to dial in relief you use string tension. It's made precise relief adjustments so much simpler for me. Mostly on my own guitars, but in general I would think.

I'll level at tension (or just about) for the B and E then back off slightly for the D and G and back off more for the bottom 2. It usually leaves me with a nicely graduated relief and has been very predictable.

Author:  joshnothing [ Fri Feb 11, 2022 4:43 am ]
Post subject:  Re: Minor upbow / maxed out rod

Thanks Burton, I’d been looking at those levellers but hadn’t heard from anyone that was using them. I do remember reading a post from Laurent Brondel a while ago too about using L-shaped aluminium extrusion to get under the strings and level under tension too.

To close the loop on this, I gave the neck a day to settle, threw on the extra washer but still felt I didn’t have quite the adjustment range. So I loosened the rod slightly and levelled out the relief. Restrung three times during levelling to check how things were tracking and all seemed well. Finished the setup today, ended up at .004” relief with the 3/64ths under the top strings that this guy wanted. As always thank you all for your guidance!

Author:  Hesh [ Sat Feb 12, 2022 5:18 am ]
Post subject:  Re: Minor upbow / maxed out rod

Good going Josh, sounds like she's singing pretty again thanks to you man! Very cool!

Author:  Lou Thier [ Tue Feb 15, 2022 12:27 pm ]
Post subject:  Re: Minor upbow / maxed out rod

Barry Daniels wrote:
Some truss rods max out because you hit the end of the threads. A thick washer under the nut may give you several more turns.



this here. sometimes ive had to add a couple to get desired results.

Author:  Barry Daniels [ Tue Feb 15, 2022 12:49 pm ]
Post subject:  Re: Minor upbow / maxed out rod

I bought a box of special extra thick washers from McMaster Carr specifically for this purpose.

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