Sharp Frets Suck

Reader Question: My Guitar Has Sharp Fret Ends. Should I File Them?

Bob Asks:

“My electric guitar’s fretboard is very dry, so the fret-ends have started protruding and feel sharp. What should I do? Should I buy a fret file and file them down? Will oiling the fretboard with F-One oil fix the issue?”

Hi Bob:

First, when it comes to sharp frets, I never recommend immediately reaching for a file. That can come later, if a more conservative approach doesn’t work first.

Next, while your guitar’s fretboard will definitely benefit from the Music Nomad F-One oil, it won’t fix the issue you’re having with sharp fret ends.

Let’s dive in…

What Causes Protruding or Sharp Frets?

Sharp frets (or “razor fret” as we like to call it) can happen for one or more of the following reasons:

1. Low humidity (lack of moisture)

This is the most likely and most common reason for sharp frets–especially if they were fine before and then suddenly appeared. The guitar has been exposed to excessively low humidity (below 45%) for too long and the fretboard wood has literally shrunk, causing the edges of the fretboard to pull back, leaving the metal fret ends sticking out. Oil alone won’t fix this.

If you want to learn more about this, you can read my in-depth article about how humidity affects guitars.

2. Unseated frets

Sometimes fret ends can actually pop up out of the fret slots. This will make just those frets (the ones that popped-up) feel sharp. You can tell whether this is the problem if you’ve only got a few sharp fret ends, but the rest feel fine.

3. Poor workmanship

This is the least-likely reason, and usually only an issue on very cheap guitars. The factory just didn’t file the ends properly. This usually isn’t the case though if the sharp frets weren’t there before and then suddenly appeared.

Here’s What to do (First) About Sharp Frets

Whenever a guitar comes to me with sharp frets, the first thing I do is tackle #1 (possible under-humidification). It’s not only the most likely reason you have sharp frets, but the remedy is also the least invasive procedure. Not to mention that under-humidification needs to be addressed anyway.

So, we need to get moisture back into your guitar’s fretboard. Essentially, we want that wood to swell back out to where it’s supposed to naturally be. Before you begin, here’s what you’ll need:

The Procedure

  1. First, follow the humidifier manufacturer’s instructions for soaking the sponge and gently removing excess moisture (from the sponge). Don’t squeeze it to death. You want the sponge very wet, but not dripping.
  2. Next, put your guitar and the humidifier into the trash bag, with the guitar resting flat on it’s back inside the bag. Since the fretboard is what we need to fix, place the humidifier inside the bag just under/behind the neck (if acoustic, do NOT put it in the soundhole).
  3. Seal the bag, but leave a little air inside, to give the moisture enough space to circulate around the neck. Don’t go nuts and blow the bag up like a balloon. You just want a little extra air in there.
  4. Leave the guitar lying on its back and don’t open the bag for 7 days.
  5. On the 7th day, open the bag and check your fret ends.
  6. If the fret ends still feel sharp, re-wet the humidifier, put it back in the bag with the guitar, and re-seal the bag.
  7. Wait another 5-7 days (remember not to open the bag during this period), then check the frets again.

Still Got Sharp Frets?

After this intensive moisture treatment, if you STILL have sharp fret ends, then I would recommend taking the guitar to a professional tech or repairperson. They’ll determine whether your frets need to be filed and/or re-seated, and be able to do the work without scratching your guitar. If you’re inexperienced at this and attempt to file the frets yourself, you will most assuredly scratch the edges of your fretboard or the body of your guitar.

However, if you really want to tackle this yourself, here’s is a good article on how to perform the procedure: Fixing Fret Ends That Stick Out in Dry Weather, by Stewart-MacDonald.

Tools suggested in that article:

As you can see, these tools ain’t cheap, so it’s probably cheaper and safer to just take your guitar to a pro and get a price quote first, before buying specialized tools like these.

A Few Final Tips and FAQ’s

Shouldn’t I put the humidifier in my acoustic guitar’s soundhole?

If you are doing this procedure to an acoustic guitar, you may be tempted to put your humidifier in the guitar’s soundhole–especially if it’s labeled as a “soundhole humidifier.” Don’t do this. Putting the humidifier in the soundhole really only benefits the body of the guitar, not the neck.

It’s the fretboard that needs help here, so putting a humidifier into the soundhole defeats the purpose and robs the fretboard of needed moisture.

Why not just put the guitar in its case with a humidifier?

Putting your guitar inside a trash bag with a humidifier may sound odd or extreme, but for a situation like this it’s necessary. Simply putting the guitar inside its case with an in-case humidifier is fine for everyday humidity regulation–on a guitar that doesn’t have a problem.

However, if your fretboard wood has shrunk to the point that the fret ends are actually sticking out, you’ve got a problem and need to be more assertive about getting humidity back into it. Guitar case interiors are usually too tight to let much moisture or air flow around around the guitar. Also, the plush materials inside most guitar cases soak up some of the moisture–which really needs to be going to your guitar instead.

What about leaving the guitar out on a stand with a room humidifier?

The same issues apply here as with leaving the guitar inside its case with a humidifier. It’s just not going to get enough moisture into a guitar that’s suffering from being under humidified (what we like to call a “dry guitar”). Like an in-case humidifier, an in-room humidifier is fine for everyday maintenance–after we’ve got the guitar’s wood back in balance.

What if I can’t keep the humidity at the proper level? Won’t the issue just come back?

Yes, the issue can indeed come back. If you live in an excessively dry climate where your guitar is exposed to humidity well below 45% the majority of the time, this is going to be a recurring problem for you. In this case you may indeed benefit from simply having the frets filed back.

Final Thoughts

So, before you reach for that file (or fretboard oil), reach for a humidifier instead and get your guitar back to an ideal humidity range of 45% – 55%. If that doesn’t resolve the issue, then and only then should you consider filing them (or letting a pro do the work).


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