You may not need a new nut – You can do this!

The biggest obstacle to doing your own nut work is needing a nut file set costing over a hundred dollars. And it’s true that none of the cheap alternatives are worth the money or trouble.

So how am I going to show you how you just might be able to fix your nut professionally and spend only sixteen dollars? Buckle up and read on!


I’d just replace it with a pre-slotted nut.”

– Bad idea!

Some of you are about to click away cause you’re thinking – “I’d just replace it with a pre-slotted nut.” – Bad idea!

Why “bad idea”? For one thing, they come too high. They have to be made high in order to fit most situations. It’s expected that you’ll file the nut slots down to specs.

“But I can just file the bottom of the nut”, you say. Yes, you can. But pre-slotted nuts are generally filed flat and perpendicular because the slots are merely intended to be markers.

You’re supposed to file slots downward toward the tuner keys to avoid bending strings at the rear of the nut. You’re also supposed to round the bottom of the slot’s exit. And on 3×3 tuners, you should widen the exit toward the tuner key side for D & g slots to avoid tuning issues and “pinging”.

Nut & saddle jig

Also, when filing/sanding the bottom of the nut it’s all too easy to not keep it perfectly flat or to accidentally take too much off one end or the other. (Don’t ask me how I know!)

With some guitar models, you’d risk cracking the finish around the nut or damaging your guitar in other ways if you try to replace the nut.

So What’s the Deal With Low Nut Slots?

When nut slots are too high, the fix is easy, if pricey – you merely need to file them down to spec – with a $130 nut file set! (And don’t forget sales tax!) But if even just one single slot is too low, people usually replace the entire nut.

Well, it makes sense. I mean, you can’t replace just one nut slot, can you? Well, in a way, you CAN!

First, let’s discuss why we even care if a nut slot is low. A lower slot means you pull less string when fretting and therefore have better intonation, right?

Well, yeah… but there’s a point too far. It’s a bit like taking photos at the Grand Canyon. The closer to the edge you can get, the better that selfie is likely to be — but go a bit further and … OOPS!

When a nut slot is too low, its string will contact the first fret when played open. It can be subtle, where you don’t actually hear a buzz yet, but there’s some loss of tone and sustain.

Low nut slot tester
My DIY nut slot tester

How Do I Test Nut Slot Heights?

We’ll use string clippings from a set of nines as gauges. When fretted at your highest fret (up at the body), you should be able to slide a b-string under each unwound string without it touching (bending). You should be able to do the same with wound strings using a g-string as a gauge. If your string gauge bends, that slot is likely too low.

How can you be sure the open string will contact the first fret? That’s what I wondered. After all, I have seventy-six-year-old ears! Well, I never need much of an excuse to buy or build a new tool. (See above image)

How does it work? I clip the alligator onto the grounded bridge, then hold the mini-prong against the end of the first fret while I pick the string with about the intensity I intend to strum with. If the red light comes on or flickers, I know the string is making contact and the nut slot needs attention.

How Do I Fill a Low Nut Slot?

Dam each side of the slot

Step one is to ensure our filler stays in the slot by “damming” each end with a tiny strip of painters tape. In the pic above, I’m using tweezers to help me place and stick the tape. First I line up the top of the tape strip with the top of the nut, then I press the tape against the side of the nut and the fretboard.

Fill the slot with baking soda

I’m known for using tools for just about any purpose except the one they were made for and I abuse these dental tools regularly! This one comes in handy for filling the nut slot with baking soda. It’s best to just use a thin layer, a sixteenth of an inch or so, at a time, but one layer is usually enough.

Here I’m tamping the soda down using a string clipping

Tamp the soda in firmly. A string clipping of the same size of this nut slot is perfect for the task. I bent the end with needle nose pliers, making the perfect tamping tool.

Adding a drop of thin (#10) CA glue

I used a precision extender tip to avoid getting CA glue on the fretboard, and let a tiny drop fall into the slot, soaking the baking soda. A blast of Insta-Set (because I’m too impatient to wait the recommended sixty seconds!) cures things nearly instantly. If you think you might need more height, add another layer of baking soda & CA.

Lastly, file the slot down to specs

Now, we’ll file that slot down to spec. But wait – at the beginning of this article, I said you wouldn’t have to spring for a $130 nut file set. So what gives?

Single nut files are $16 at MusicNomad on Amazon

You can buy single nut files from MusicNomad. Current price is just sixteen dollars on Amazon! This would allow you to build a nut file set piecemeal for a total of ninety-six dollars for a set of six! Tell ’em Hank sent ya!

Low nut slots
Finished nut

If you have multiple low nut slots, then a shim may be in your future. Let’s cover nut shims in our next article.