I currently have a Fender Strat which I set up with 12-56 strings about 2 years ago and have been playing comfortably since, using mostly standard tuning. However, I've decided to switch my strings to 9-42s as the heavy set doesn't fit my playing style anymore. Because of this, I'm wondering whether i'll need to buy a new nut as my current nut has been filed for 12 gauge strings so the grooves might be too wide? I'll clearly need to do a complete setup of my guitar and adjust my truss rod, but will my nut need changing as well?

3 Answers 3


In all the guitars onto which I've put much lighter strings, (dozens, if not more) there's not been a problem. The tension will pretty well keep the strings from rattling round in the slots. Should there be a problem - very unlikely - then a tiny strip of paper will sort it out.

Obviously, the intonation will alter, needing adjustment of the saddle positions; the neck tension may need changing, and the action will probably need a tweak. You may even want to move the pups slightly higher, too.


You don't normally need to worry about the nut slots being a little wide - usually the break angle of the string over the nut plus the tension on the string is sufficient to keep the string in place. This assumes that the nut slot has been correctly filed into a suitable (roundish) U- or V- shape - if it's filed too flat at the bottom, that increases the potential for lateral movement of the string.

Try it, and don't try to deal with the problem unless you find there actually is one.

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    In my experience this is generally true, though I had a guitar with an inexpensive nut that was not fitted well to begin with that didn't tolerate light gauge strings very well until I replaced it. It took several weeks to pinpoint the issue and I wouldn't think it's particularly common on a guitar that has been performing fine already. More common in my experience is nuts that are too narrow to put heavier strings on. A quick fix that keeps that from making tuning a nightmare is to scribble with a pencil onto a small piece of paper until it's covered in graphite, then rub it into the slot. May 17, 2018 at 20:17
  • @DarrenRinger sometimes if you don't have proper files and you are 'feeling lucky', an old string of a similar gauge to the one you want to put on can be pulled through the slot in a 'sawing' action to widen a slot in a somewhat controlled way. I'm not saying it's the right tool for the job but if the nut in question is on a beater guitar that cost you less than a decent file would, it's an option! May 17, 2018 at 20:22
  • @DarrenRinger - yet another reason why I prefer guitars with a zero fret !
    – Tim
    May 17, 2018 at 20:44
  • @Tim - yes, that's a good argument indeed for zero frets. But do they sound exactly the same as no zero fret? At least theoretically, the strings could lose more energy in rubbing side to side on the zero fret when open. But it might well be that this effect is negligible- I've never tested it myself. May 18, 2018 at 13:35
  • @ScottWallace - On my weapon of choice for the last 40 yrs, there's no difference between the sound of the open string because of its zero fret, as far as I can tell. Sounds like any guitar with just a nut. They can't really rub any more than they do at the other end. It's a node with theoretically no movement.
    – Tim
    May 18, 2018 at 15:23

I changed from 10s to 9s on my Strat and because of the now-too-wide nut slots, it buzzes like crazy on all open strings.

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