Can Strings Cutting Into Bridge Cause Buzz?

[Jeff Schiefer]

Hey All, newbie on this forum, so please excuse me if this has been covered before.

Looking for some advice on an issue I'm having with a Yamaha FG340, circa 1980. Several years ago, I installed an under-bridge pick-up, and did some other work on the guitar– replaced some frets, replaced plastic nut with bone, replaced old plastic saddle with bone saddle, lowered the action a little (lowered saddle, adjusted truss rod).

Over time, the strings seem to have cut into the bridge wood in front of the pins pretty deep. I get a real twangy sort of buzz from the high E and B strings when played open. I discovered if I put some shims under the strings in the grooves they cut in the wood, I eliminate the twang/buzz. (Using thin pieces of plastic for shims.)  Since this fixes the twang, would you say the issue has to do with the grooves, or with the saddle being too low on that end? The saddle is not that old, and barely any groove wear in it, but it is pretty low on the first E side. The strings look like they are making decent contact with the saddle. I use Light gauge strings.

I ordered a new saddle, intending to shape it to sit a little higher on that end, but I hate to raise the action again if I don't need to.

Any suggestions/thoughts?

I don't understand why the shims are correcting the problem for me when I know many people ramp from the string holes intentionally. I can attach some photos if it will help diagnose the issue (if there is an option for attaching photos here).

Thanks in advance for any suggestions.

[steven gallagher]

Jeff,

You'd better read that article about nut action again. Then tell me why you think a .016" piece of string should fit between the string and fret.

Hint: a human hair is about 5 mils and paper is around 10 mils.

[Jeff Schiefer]

Steven, yeah– i know it is supposed to be VERY close on the 1st E, first fret. But there supposed to be a little gap, right?

Part of the article said "If you're having difficulty seeing the tiny gap under the string, try this: With the string pressed down between the second and third frets, tap on the string very close to, but not right over, the first fret. If there IS a gap that's too small to see, you'll hear a little click as the string hits the frets. Cute trick, eh?"

When I try this, I do not get ANY click, or discernable feel of hitting the fret. Yes, a piece of paper went through, but that was undoubtedly rubbing top or bottom. Doing a quick Google search on common notebook paper thicknesses, I see approx. .003 - .004" Is that enough? I like it low, but if that's causing the buzz?????

I know there is no standard for what that space should be, it's up to everyone's personal preference. I was going by a StuMac article I found that recommended .013" for a steel string acoustic.

http://www.stewmac.com/How-To/Online_Resources/Neck_Building_and_Re...

My plan at this point is to try the bone dust/CA trick, but only fill the slot enough to raise the string enough to get rid of the buzz. That won't take much. Won't need to fill the whole slot and re-cut. So am thinking I'll just get a set of torch cleaning picks, since all I really need to do is smooth out the fill after it hardens. I know about keeping the right angle.

[Paul Breen]

Jeff, you should also pick up a set of feeler gauges, that is what I use to check string height at the first fret. You have to watch closely and feel with individual feeler gauges, removed from the set. When the size is close, you may not feel the blade but if you see the string move up and down slightly, it's too tall.

The method I use was taken from one of  Don Teeter's books and the string is fretted between the 3rd and 4th frets. I use a value of .005" a the first fret on the treble E and add .001" for each larger string, ending up at .010" at the bass E.

This is what has worked for me and is repeatable but there are other methods. My suggestion would be to read what you can on the topic. Without some basic tools though, you will be at a disadvantage.

[Jeff Schiefer]

Yep. I actually have a set... somewhere. I wasn't able to find them the other day when I started looking into all this. I can pick up a set an NAPA.

Thanks for the suggestion from the Don Teeter book. I'll start there (.005).

[steven gallagher]

Jeff,

I thought we were talking about the gap while you were holding the string down at the 3rd fret.

The .013" action from the StewMac article is for an unfretted string. 

[Jeff Schiefer]

Well, dang you're right! Thanks for pointing that out Steven!

[Mark McLean]

Jeff

I think you have answered your own question when you say that you can't feel any click when you tap the e-string onto the first fret.  Probably it is already sitting on the fret because the nut slot is too low. 

If it is the only string that is too low, then filling the slot is the right plan.  If they are all too low you could put a shim under the nut and raise all of them. 

Filling the slot with CA and dust usually involves filling the whole slot and then recutting it to the correct depth.  In practice it is very hard to JUST ADD A LITTLE BIT, and bring it from too-low to just-right. 

[Jeff Schiefer]

I believe it's the first 2 strings that are just a bit too low. Once I get to the wound strings, they seem to be okay.

I hear you on the CA/dust filling. I'll think about that some more then. May have to invest in some real nut files. I need to find my feeler gauges and check it more accurately with those. (see my rep[ly to Paul above) I MAY have .005' of clearance. If so, I may just leave it alone. Since I gave the neck a small adjustment last week, I only get a slight buzz when I play those strings open, HARD. And being light gauge strings, that may be just par for the course.

[David Farmer]

Jeff, I'm confused, you have a buzz problem that you were able to eliminate by putting shims in the string slots at the bridge. What points to a nut problem? You seem to be ignoring the results of your shim test.

If you put a straight edge (the string works) across any three frets and have .003"-.005" clearance over the middle fret, it would be considered way too much. think of the nut as a #0 fret. If you a have notebook paper clearance over the first fret when held down between 2 and 3, Nut height is not the problem.