String damage exampleWhile strings don’t break often, it can happen. And when the dreaded string break occurs, you might be asking yourself, why? Was it something you did? Was it the weather? Anything?

You don’t have to be a luthier or guitar or uke tech to hunt problems down and fix them. Some observational skills and knowing what to look for will more than suffice.

There are a myriad of reasons why strings break. Sometimes they’re just old and fatigued, and can no longer withstand the constant stress required to maintain them at pitch. They’ve been plucked, strummed and rasqueadoed to the point where they’ve just had enough.

But often, and perhaps more often than one might think, string breakage is the direct result of some sort of string trauma that’s usually caused by an abrasive action between the string and either the fulcrum of the saddle or the nut slot.

Treble string damage at nutExperience has taught me that string breakage more likely occurs at the nut than the saddle. What typically happens (at least on unwound strings) is one string gets abraded or cut as it travels through the nut slot. The damage is the result of a sharp leading or trailing edge on the slot, or the slot is just not wide enough to allow the string to seat itself properly. The damage is sometimes severe enough to detect with visual inspection, especially on a clear nylon string, though sometimes less apparent on carbon strings which are more translucent.

String check at nutAs an alternative to a visual inspection, loosen the string and lift it above the nut. Use your thumb and forefinger and run them along the section of string in front of and behind the nut. If you feel any roughness along the surface of the string, the nut is most likely damaging the string as it tightens or loosens while you tune your instrument.

Bass string damage at nutWound bass strings react a little differently due to the different nature of their construction, but the result is the same. The metal winding protecting the filament core is separated as it runs over the sharp leading or trailing edges of the bass nut slots, exposing the core. Over time, as you tune and re-tune, the exposed filaments are either cut or abraded, ultimately causing a breakage.

It doesn’t take much time or effort to eliminate the burrs in the slots that compromise string integrity. Nor does it take a lot of fancy tools. There’s no need for files, as you’re not trying to remove a lot of material.

I’ll share with you an easy way to make minor adjustments with just a small piece (about 1" x 1") of 1200 grit emery paper. If you need to widen the slot a bit, you can use 320 or 400 grit papers. These finer grit papers should be available at any good hardware store. I don’t recommend emery cloth as it isn’t stiff enough.

Fold the square in half and run the folded edge back and forth in the slot making sure you are polishing the bottom of the slot and the leading and trailing edges. This requires angling your motion a bit. You’ll feel a little resistance as the emery paper cuts and polishes the inside of the slot. As only the folded surface is doing the work it may get clogged with sanding dust after just a few passes. You’ll know when this happens, as the emery paper will slide through the slot without any resistance. Make another fold to create a fresh cutting surface. I very rarely have to do this more than a couple of times to achieve a polished slot. While you may not be having issues with all slots, it doesn’t hurt to polish them all as a preventive measure.

Sandpaper folding and nut polishing

So there you have it! Another quick little tidbit to put in your guitar survival toolkit.

Of course, there are many other causes for string breakage, but for now, this one will help you avoid at least some of those unexpected string breaks.

Want to learn other causes of string breakage? Subscribe to the ASN eNews today.