I have adjusted the neck relief (or neck bow) on many (approx. 20 or more) of my guitars without having any problems at all. While I’ve owned a Collings D2H and D1A, I’ve never needed to adjust a Collings truss rod for neck relief until this week end when I received a CW MhA that I just bought. I ran into a problem and thought I’d record some solutions in case it would be of help to others. (By the way, one of my solutions below allows you to use a standard allen wrench instead of a ball-end allen wrench.) I found some help on this site but it was scattered around in several different threads. So maybe this can be a more complete source of info if you have the desire and inclination to adjust your guitar. Also, much of what I have learned about guitar setup is from Frank Ford on his frets.com site. (I can’t thank you enough, Frank. You have made it possible for my guitars to be sooooo much easier to play.)

There are 2 main reasons to adjust neck relief:

1. To stop string buzz.
There can be many reasons for buzzes, but assuming you have good even frets and no loose parts, too little neck relief can be the cause. In this case you want to increase the neck relief which increases the space between the strings and the fretboard.

2. You want to make your guitar easier to play.
Easier by moving the strings closer to the fretboard. The biggest impact of reducing relief (straightening the neck to take some of the bow out of it) is in the upper register in the middle of the bow. As you straighten the bow the strings move most in the middle of the bow, therefore reducing the gap between the strings and the fretboard. While the strings also move closer in the lower register in the first position (i.e. first 3 frets), the impact is not as great here. But any little bit helps. (Lowering the nut action is what really has the biggest impact in improving playing the first position 3 frets. This is the most often missed opportunity by most guitarists to really improve their ease of play.)

Collings requires a 5/32” ball-end allen wrench to adjust the truss rod according to their web site here with their helpful diagram:
http://www.collingsguitars.com/images/truss-rod-adj-lg.gif

Unfortuantly, I know of no place where Collings tells you why or HOW to adjust their truss rods. The picture on their link above is all they give us as far as I know. They will mail you a free 5/32” ball-end allen wrench if you call and ask for one. Or you can buy one from Lowes, Home Depot or another hardware store.

Neck relief is measured at the 6th fret. It is the distance between the bottom of the string and the top of the 6th fret. The distance needed here will never be agreed on by players because of all the variables. The main variable is how hard the guitarist plays the strings. The more force used (to play very loud) the more relief is needed to avoid buzzing. Taylor recommends 10 thousands of an inch (about the thickness of a business card) for the space at the 6th fret. Frank Ford says hard bluegrass players may need 26 thousands. I play fingerstyle and have found 5 thousands works fine for me. So have many other guitarists. In fact, some guitarists play just fine with a straight neck with no relief. The trick is to go as low as you can to get the easiest play without string buzzing with your normal play and without having a back bow of your neck.


Here’s a couple of approaches to change neck relief (adjust the truss rod):



METHOD ONE FOR COLLINGS GUITARS NECK RELIEF ADJUSTMENT

1A. Check the neck relief so you know and remember what it is.
Here’s how you check neck relief:
- Tune the guitar as you regularly do with your normal string tension. (i.e. to concert pitch, or tuned down, or open tuning – whatever is “normal” for you)
- Hold the guitar on your lap, in the playing position.
- Using your left index finger, fret the Low E at the 1st Fret. Or put a capo on the first fret (easiest).
- Using the thumb on your right hand, fret the Low E at the 14th fret.
- Using the index finger of your right hand, push the string down at the 6th fret and eye the distance of the gap as you close and then open the space between the string and the top of the 6th fret. You do not have to actually measure the gap, but you can use a feeler gage to measure the gap if you want to and use the guide line above. Again, this gap measurement is not absolutely necessary if you can eye it and remember it.

1B. Put a 5/32” ball-end allen wrench into the truss rod nut.
With strings at normal tension, put the ball-end wrench into the truss rod nut inside the guitar just under the top at the end of the neck joint. With the strings at full tension, this is not easy to do, but it is doable. I put my wife’s small make-up mirror inside resting on the back of the guitar so that it looked up at the truss rod nut. This way I could see the nut and the ball-end allen wrench at the same time and put the end of the wench into the nut. It is important to wiggle the wrench back and forth a tiny bit to make sure it is fully seated in the nut.

1C. Turn the wrench and nut to adjust the neck relief.
To reduce neck relief and straighten the neck, tighten the nut by turning the wrench and nut ¼ turn clockwise when facing the nut looking at it from the sound hole. ¼ turn is the distance from say 6 O’clock around to 9 O’clock. Or 12:00 O’clock around to 3:00 O’clock, etc.. (As Bryan Kimsey pointed out in another thread on this subject, talking about turning "left" or "right” is confusing and therefore not helpful.)

To increase neck relief and add more forward bow to the neck, loosen the truss rod nut by turning the wrench and nut ¼ (one quarter) turn counter-clockwise when facing the nut looking at it from the sound hole. ¼ turn is the distance from say 6 O’clock back to 3 O’clock. Or 12:00 O’clock back to 9:00 O’clock.

1D. Re-check the neck relief and determine that it either increased or decreased as you expected.
If it did not, you turned the wrench the wrong way. Don’t worry, changing the nut the wrong way only ¼ turn or even ¾ turn will not hurt anything. The people who do damage here are the ones who keep turning and turning without checking to see the results and without knowing what they are doing. If you are checking the relief with every adjustment as you go, you will KNOW what is happening long before you could get into trouble and damage anything.

If you are not sure if it increased or decreased by eyeing it, then look closely at the relief again (or measure it), repeat step 1C and turn another ¼ turn in the same direction as your first ¼ turn, and then repeat this step 1D to determine that it is increasing or decreasing the relief gap as you expect.

1E. Play your guitar and determine if there is any buzzing.
- If you do not have buzzing, and your goal was to increase relief to stop the buzzing, then you are done.

- If your goal is to decrease your relief to improve playability, then keep decreasing it (straightening the neck) until it buzzes with normal playing. Then go back and increase the relief so that the buzzing stops. If your saddle is very high you might not get your strings to buzz. In that case, or any case, stop straightening the neck if it gets to perfectly straight. This is when there is no gap between the string and 6th fret when you check the neck relief. Do not keep tightening the truss nut. You do not want the neck to have a back bow. You want it have a slight forward bow in most cases.



METHOD TWO FOR COLLINGS GUITARS (NO BALL-END WRENCH NEEDED)

2A. Check the neck relief so you know and remember what it is.
Here’s how you check neck relief:
- Tune the guitar as you regularly do with your normal string tension. (i.e. to concert pitch, or tuned down, or open tuning – whatever is “normal” for you)
- Hold the guitar on your lap, in the playing position.
- Using your left index finger, fret the Low E at the 1st Fret. Or put a capo on the first fret (easiest).
- Using the thumb on your right hand, fret the Low E at the 14th fret.
- Using the index finger of your right hand, push the string down at the 6th fret and eye the distance of the gap as you close and then open the space between the string and the top of the 6th fret. You do not have to actually measure the gap, but you can use a feeler gage to measure the gap if you want to and use the guide line above. Again, this gap measurement is not absolutely necessary if you can eye it and remember it.

2B. Put a capo on the first fret and loosen the strings.
The capo keeps control of the strings to avoid a major mess. Pull the strings slack from the peghead side to the sound hole side to create enough opening at the sound hole. Loosen them enough so you can easily put your whole hand into the sound hole without strings painfully cutting into your hand.

While it is best to change the neck relief at normal string pitch it is not mandatory. I found step 1C difficult because my ball-end wrench kept slipping out of the truss rod nut and I did not want to strip the nut (damage it). Neither was the nut turning. Therefore I was getting no adjustment. So I resorted to a fool proof way to avoid damaging the nut and achieve my goal of neck relief adjustment. This method is more time consuming/work, but its not that bad.

2C. Put a standard 5/32” allen wrench into the truss rod nut.
Use a 5/32” standard (not ball-end) allen wrench which is about 2 ½” long by 1” long. This smaller length will allow you to swing the wrench around 180 degrees if needed. The longer ball-end wrench will not allow this ease of use, but it will work in a much more limited range if that is all you have. Put your whole hand into the sound hole and use it to seat the short 1” end of the allen wrench into the truss rod nut.

2D. Turn the wrench and nut to adjust the neck relief.
To reduce neck relief and straighten the neck, tighten the nut by turning the wrench and nut ¼ turn clockwise when facing the nut looking at it from the sound hole. ¼ turn is the distance from say 6 O’clock around to 9 O’clock. Or 12:00 O’clock to 3:00 O’clock, etc.. (As Bryan Kimsey pointed out in another thread on this subject, talking about turning "left" or "right” is confusing and therefore not helpful.)
To increase neck relief and bow the neck more, loosen the truss rod nut by turning the wrench and nut ¼ turn counter-clockwise when facing the nut looking at it from the sound hole. ¼ turn is the distance from say 6 O’clock back to 3 O’clock. Or 12:00 O’clock back to 9:00 O’clock.

2E. Re-tighten the strings to your normal pitch (i.e. concert pitch or whatever is normal for you.)
Leave the capo on until there is some tension on all the strings so that you continue to control the strings and avoid a mess.

2F. Re-check the neck relief and determine that it either increased or decreased as you expected.
If it did not, you turned the wrench the wrong way. Don’t worry, changing the nut the wrong way only ¼ turn or even ¾ turn will not hurt anything. The people who do damage here are the ones who keep turning and turning without checking to see the results and without knowing what they are doing. If you are checking the relief with every adjustment as you go, you will KNOW what is happening long before you could get into trouble and damage anything.

If you are not sure if it increased or decreased by eyeing it, then look closely at the relief again (or measure it), repeat steps 2B, 2C, and 2D and turn another ¼ turn in the same direction as your first ¼ turn, and then repeat steps 2E and 2F to determine that it is increasing or decreasing the relief gap as you expect.

2G. Remove capo and play your guitar and determine if there is any buzzing.
- If you do not have buzzing, and your goal was to increase relief to stop the buzzing, then you are done.

- If your goal is to decrease your relief to improve playability, then keep decreasing it (straightening the neck) until it buzzes with normal playing. Then go back and increase the relief so that the buzzing stops. If your saddle is very high you might not get your strings to buzz. In that case, or any case, stop straightening the neck if it gets to perfectly straight. This is when there is no gap between the string and 6th fret when you check the neck relief. Do not keep tightening the truss nut. You do not want the neck to have a back bow. You want it have a slight forward bow in most cases.

OK, there you have it. Ed’s step-by-step method for adjusting a Collings guitar. This is not intended to be the “end-all” or “final word” on neck relief. I just wrote this with hope of helping someone. Especially since the Collings adjustment was more challenging (more of a pain) than most other guitars I have worked on. I’m sure others could improve upon this, but the level of detail I've covered should answer many questions and put most people who lack experience with this well on the way to getting this done themselves instead of depending on others.

Good luck!

Disclaimer: While most people should be able to make truss rod adjustments IMHO, if you are not able to follow instructions or you are not “mechanically minded”, then get someone else to do this for you. If that is the case, why not at least learn how to check his work by following and learning just Step 1.

This message has been edited. Last edited by: Sugarlander,

Fine post. Just a few points.
You can slacken the tension on the strings to make the adjustment to the truss rod. It is probably not necessary most of the time but it might not be a bad idea on that initial adjustment on a guitar you are not sure about. Sometimes truss rods do bind and/or the truss rod nut freezes up and you don't want to force things and damage the rod - or at least you can turn the rod a little counter clockwise (loosen) a bit at first to see how tight it is. If tight a bit of oil on the threads could be helpful.
Of course when checking for buzzing do note on which fret(s) it occurs as that makes a difference in the analysis, for example buzzing when fretting on a worn down fret or due to an unseated fret higher up the neck. Also of course be sure the other adjustments at the nut and bridge are set right. Finally is there is any question about how the guitar has been treated recently check for signs of hydration or dehydration.
Rick

Rick,

I agree with you. These were good points to add.

Thanks,
Ed