truss rod adjustment

dansprucefir
Posts: 44
Joined: Sat Nov 10, 2018 12:53 pm
Location: Athens, GA

truss rod adjustment

Post: # 5498Post dansprucefir
Wed Apr 27, 2022 12:35 pm

Hey all,
With humidity changing (now that it is almost May) my OM1AT has started to display some "sitaring" on the third string when fretted (or capoed). I used the Collings truss rod adjustment tool to turn the truss rod about a quarter turn counterclockwise and it may have improved some. I am considering another eighth to quarter turn but don't want to go too far. There was very little relief before my initial tweak. Can anyone provide advice on how far is too far?
Thanks in advance!
Dan

dbintegrity
Posts: 16
Joined: Sun Mar 24, 2019 12:42 am

Re: truss rod adjustment

Post: # 5505Post dbintegrity
Thu Apr 28, 2022 10:28 pm

Hmm... I'm not sure if adjusting the truss rod is the correct answer here... I prefer a straight neck and taller saddle. If you already had slight relief in the neck, I don't think adding more is the answer... unless you mean it had a back bow... different story... I wonder if the guitar may have dried out through the winter months and the top sunk little... I'd check that the guitar is properly humidified, maybe add a shim under the saddle



...

dansprucefir
Posts: 44
Joined: Sat Nov 10, 2018 12:53 pm
Location: Athens, GA

Re: truss rod adjustment

Post: # 5506Post dansprucefir
Fri Apr 29, 2022 11:49 am

Thanks db. It was humidified all winter but I did have the action lowered this winter as well. I may order a new saddle from Collings and start there.
Dan

dbintegrity
Posts: 16
Joined: Sun Mar 24, 2019 12:42 am

Re: truss rod adjustment

Post: # 5509Post dbintegrity
Sun May 01, 2022 11:06 pm

Always good to have an extra saddle. My guess is that returning to a taller saddle will probably remedy the issue, but as the summer months come the humidity may cause the top to swell and youll want to go back to the lower saddle…

West R Lee
Posts: 30
Joined: Sat Jul 25, 2020 6:10 am
Real Name: J. D. Brown

Re: truss rod adjustment

Post: # 5523Post West R Lee
Fri May 06, 2022 7:00 am

I've followed these (Collings directions) to a tee on a few occasions. The fact is though that it should be the last thing you do to lower action. I see "relief" and "action" as two different things, both of which result in elevated string height from the fret board. Action should first be lowered by sanding the saddle, which effects string height all down the fretboard. Only if the neck is bowed forward or with a back bow should the truss rod need adjusted. If you follow Collings' directions to a tee, as I've done, you can adjust your neck back to straight.

And yes, I like my acoustic with very low action, and play light gauge strings, so I'm pretty particular where my string height is.

So my suggestion would be to simply check your neck for straightness using a feeler gauge and a capo, ensure the neck is perfectly straight, then shave a bit of saddle if needed.

From Collings: What are the factory specifications for acoustic guitar setup?
String Height (measures top of fret to bottom of string):
Bass-side string height at 12th fret: 3/32"
Treble-side string height at 12th fret: 2/32"

Relief (measures distance from top of fret to bottom of string while fretting the 1st and 15th fret):
Relief at 5th Fret: .005" (a post-it note folded in half is about .005")

We consider these measurements to be a "medium" action height. You should have some room to lower the action from these measurements, but keep in mind that an ultra-low action usually requires lighter playing or adjusted technique to prevent buzzing. Feel free to give us a call if we can be of any help.

dansprucefir
Posts: 44
Joined: Sat Nov 10, 2018 12:53 pm
Location: Athens, GA

Re: truss rod adjustment

Post: # 5526Post dansprucefir
Fri May 06, 2022 6:47 pm

Thanks West! I ordered a new saddle from Collings and am going to use this info to get things back to where they should be.
Dan

West R Lee
Posts: 30
Joined: Sat Jul 25, 2020 6:10 am
Real Name: J. D. Brown

Re: truss rod adjustment

Post: # 5527Post West R Lee
Fri May 06, 2022 11:33 pm

You bet Dan. I'd just gone through all of this about a year ago. People act like adjusting the truss rod is rocket science, but it's really pretty simple.........as long as you don't get carried away. I think the danger is in going too far with that adjustment. I liked Collings' technique for tweaking relief so much, I applied the same measurements and tweaked a couple of Guild guitars using the same measurements. As I recall Dan, with my D2HA I had slight forward bow, and I was high about .009" at the 5th fret, capoed at the first and fingering the 15th fret. Checked with a feeler gauge. I adjusted by loosening the nut not even 1/8 revolution........just a little tweak. Came back and measured at the 5th and got, and still have .005". Sure makes 'em more playable.

West

West R Lee
Posts: 30
Joined: Sat Jul 25, 2020 6:10 am
Real Name: J. D. Brown

Re: truss rod adjustment

Post: # 5530Post West R Lee
Sat May 07, 2022 7:26 am

So then to recap Dan, you'll take a capo and capo the 1st fret, then you'll finger the 15th fret. Once there, take an accurate measurement with a good feeler gauge between the 5th fret and the bottom of the low E string. That measurement should be .005". if you're high there, as I was, it generally means the strings have pulled the headstock/neck up a bit (normal with string tension). So what you're going to do now is to actually flatten the fretboard. You'll need either a cut off Allen wrench in 5/32" ball end, or a 5/32" Allen with a universal joint on it (it's what I use). The nut is behind the cross bracing in the neck block. You'll have to reach up to get to it, up and around the bracing. Now you're on the truss rod nut, if you've got the same bow I had, then loosen the nut like less than 1/8 turn, and let the guitar sit a few minutes. Check the 5th fret measurement again, adjust, and so on till you get her dead nut!

West

dansprucefir
Posts: 44
Joined: Sat Nov 10, 2018 12:53 pm
Location: Athens, GA

Re: truss rod adjustment

Post: # 5532Post dansprucefir
Sat May 07, 2022 4:05 pm

Thanks West! I plan on following this exactly. One question: do you feel like a luthier needs to sand the saddle or do you think a non-luthier can do it and make sure the bottom of the saddle does not have an angle?
Dan

West R Lee
Posts: 30
Joined: Sat Jul 25, 2020 6:10 am
Real Name: J. D. Brown

Re: truss rod adjustment

Post: # 5540Post West R Lee
Mon May 09, 2022 1:14 am

If you can get the saddle flat on the bottom, without taking too much off, you'll do just fine. Just take it slow and keep the saddle square. I sand mine on a granite counter top that's flat as a pancake.

West

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