Truss Rod Adjustment

[davidbeinct]

I have an old style truss rod with the 1/4” nut. When I try turning the nut it looks to me like it just gets tighter or looser on the rod it’s threaded on to. I don’t see any change in relief. Here’s a pic:

 

[davidbeinct]

I realize it’s blurry but I think you can see the gap between the nut and what looks like a little washer. It doesn’t seem to have any effect on the relief.

 

[davismanLV]

Not sure. Does it make contact with that washer and does it get harder to turn? What's it look like when you take the nut off. Do the threads disappear into the washer? Need more info....

 

[davidbeinct]

It will make contact with the washer if I tighten it. Not sure about the thread’s disappearing. I think they do. I’ll have to look again.

 

[chazmo]

The old-style truss rods, which weren't dual-action, will not bow forward when you turn the nut counter-clockwise. The neck should be bowing forward (up) because of string tension, but yours isn't doing that. I think you've gone too far, past the limit of what the neck will bow forward. I hope that you are getting ridiculously high action with this as it is currently "set."

You should tighten that up (clockwise) until it makes proper contact with the washer on the rod. Then your only adjustment will be continued clockwise movement which will cause the rod to bow back. If you do that, make SMALL adjustments.

 

[davidbeinct]

Chazmo thanks for your answer. To be clear if I tighten it up more I should see the gap at the twelfth fret get smaller? Even really loose like that it’s got the action in a good position. Well within spec.

 

[chazmo]

Chazmo thanks for your answer. To be clear if I tighten it up more I should see the gap at the twelfth fret get smaller? Even really loose like that it’s got the action in a good position. Well within spec.

Just snug it up (very gently, no torque) against the washer, David. If you're happy with the action, don't go any further clockwise and your done. If you need to bring the strings down to the fretboard, tighten 1/8 to 1/4 turn AT MOST and check again. Do this repeatedly, if necessary, but go very slowly and probably no more than total of one whole turn and a 1/2.

The best way to check this is to eyeball down the neck to see if there's any forward or backward bow, David. It's very hard to be clear explaining this without being there with you, but if you know someone who's done TR adjustments that's the best way to learn. After the eyeball test, lay a straightedge down on the fretboard and make sure there's no gaps or humps. Then what you want is hte staightedge should land almost at the top of the bridge (or base of the saddle, if you will). If it's far off from that, you may need a neck reset and that's where I tell you to take it to a tech/luthier.

 

[adorshki]

Chazmo thanks for your answer. To be clear if I tighten it up more I should see the gap at the twelfth fret get smaller? Even really loose like that it’s got the action in a good position. Well within spec.

Right. Tightening (clockwise as you face the nut from the top of the headstock) serves to bend the rod back against the tension of the strings. Understand "flat" is usually the starting point to add some relief.

Relief is an area of greater string clearance on the fretboard, typically around the 5th-9th frets, normally created by loosening the truss slightly and thus adding in a bit of backbow, to allow the strings to clear the frets under hard strumming. It only affects action height as a side-effect of that back-bowing, and only within a very limited range. Remember action height is actually dictated by saddle height in a properly aligned neck, and the truss rod can't affect neck angle since it's contained inside the neck. It has to go where the neck goes.

If you've got good action with a loose truss, it means your neck is in pretty good shape against the tension of whatever string set you're using. I'd just back it up the washer and not worry unless you start to get some buzzing.

 

[Wilmywood]

Once you make the 1/8 to 1/4 turn adjustment. wait a while and then check it. I find on my Guilds it may take a full 24 hrs to settle.

 

[davidbeinct]

Thanks everyone for your help much appreciated.

 

[wileypickett]

Once you make the 1/8 to 1/4 turn adjustment. wait a while and then check it. I find on my Guilds it may take a full 24 hrs to settle.

I've found this to be true too.

 

[Wilmywood]

It's easy to get carried away with a truss rod and end up back where you started, or worse.

 

[GAD]

It's easy to get carried away with a truss rod and end up back where you started, or worse.

I have a fairly uncommon Guild with a nig crack in the neck likely due to someone being overzealous with the truss rod.

 

[chazmo]

ikely due to someone being overzealous with the truss rod.

Yup. Like I said, @davidbeinct , nothing more than 1/4 turn at a time. You should also allow some settle time as the other guys were saying.

That's a shame, GAD. Yeah, we've seen a lot of that over the years. Sigh.

 

[adorshki]

Thanks everyone for your help much appreciated.

Made a goof above when I said loosening adds a bit of back-bow, actually meant forward bow, as in the headstock is pulled slightly toward the bridge. In case it confused you.

Shoulda thought of this earlier:

#1 is forward bow, #2 is back bow.