Nut Slotting Gauge

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Nut Slotting Gauge For guitar and most instruments

For guitar and most instruments

Item # 2003
In stock, ready to ship!


Nut Slotting Gauge For bass

For bass

Item # 2006
Due 1+ month
Email when in stock


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Nut Slotting Gauge

About This Item

A revolution in guitar setup! Precisely measures string heights, so you can cut accurate nut slots for consistent playability.

This device that will revolutionize the way you set up a guitar.
The Nut Slotting Gauge quickly and precisely measures string heights over the first fret. When filing nut slot depths, you see your results more accurately than ever before. No more guesswork or "eyeballing" the string heights, and no more searching for elusive combinations of feeler gauges. You can custom-tailor the playability with consistent, repeatable results.

At last! A precision tool for establishing string heights!

The Nut Slotting Gauge was designed by Don MacRostie here in our R & D shop. It features an easy to read dial indicator with adjustable zero point, and it's super accurate to .001". The machined brass base fits over the strings to rest on the fingerboard, and it works with most acoustic and electric guitars, mandolins and banjos. A larger brass base is machined to fit bass string spacings. Both have gently arched bottoms to follow most any fretboard radius. Instructions are included.

The Nut Slotting Gauge is included in this money-saving set: Nut Slotting Gauge and Neck Relief Gauge Set


Trade Secrets!

Trade Secrets!

Putting the new Nut Slotting Gauge to work on a "burn victim" guitar

Dan Erlewine shows a before and after of a 1958 Gibson that's (barely) survived a house fire. It needs a new nut, and he's using the Nut Slotting Gauge to get it right the first time.


Product Instructions

Nut Slotting Gauge Instructions

How to determine nut slot depth with the Nut Slotting Gauge.

Customer Reviews

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  • 4.69 average rating from 70 reviews
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Awesome tool

(Customer's Reviews)

This makes measuring string height at the nut a breeze. It's so easy to use and very accurate. I was able to lower the nut action on my guitars, and they play so much better now. Plus, the intonation is spot-on playing in the first few frets. Stew-Mac rocks!!!



(Customer's Reviews)

Never realized all my "cheap" guitars just need the nut filed to the correct and personal height to play as good as my "expensive" guitars. If even after you struggle with countless attempts to intimate and still have tuning problems, check your nut.


Nut slotting guage

(Customer's Reviews)

Also useful for measuring installed fret height when Fat Frets won't fit into the end slot in the digital caliper.

Use it over the fret and then on the fingerboard with no fret, difference is fret height


Great Tool

(Customer's Reviews)

I hesitated getting this for a couple of years. I kept going back and reading all the reviews but wasn't quite convinced that it would be accurate enough because a couple of reviewers were not getting consistent results. I should have gone with the majority.
I measured several guitars with it and double checked the results using feelers and I get the same results from both methods. I am confident that with this gauge I get the correct measurement every time within a fraction of a second. Far quicker than my old method.
It's a great quality tool which I use every day. Should have bought it a long time ago.


A go-to tool

(Customer's Reviews)

I use this all the time. I rely on it so much. I use it not only to set string height at the nut, but to check string height at all the frets, and at the 12th fret to set action height at the bridge - I can't imagine using a ruler to do that.


Highly Accurate. Requires Careful Use

(Customer's Reviews)

This is a beautiful tool. I've read the reviews here, and believe that those who feel it gives different readings may be seeing the effect of slight variations in the fretboard, more than the accuracy of this tool.

I noticed that while over the same string (1st fret of course), the dial would move by up to 3 mil depending on exactly where I placed it on the fretboard (Meaning, sliding it closer to the string above or below the one I was measuring.) However, if I was very careful about placement, so that the radius and/or unevenness of the fretboard would not be a factor, it gave very consistent results.

I give it 5 stars because it does what it claims well, and compared to feeler gauges... There is no contest. That said, if Stewmac wants to improve it they could:

1) Print the dial in reverse... Kind of silly to have a custom tool like this, yet the user has to count backwards to figure out the measurement instead of just reading the dial.

2) Lengthen the tube/support that holds the dial by maybe 3/8th inch so that one can get their fingers in and hold onto it better.

3) Or, alternately, look at how the brass block could be made slightly larger or reshaped so a person could more easily get a thumb on to hold it in place while depressing the strings. The main problem with getting consistent readings is that it is very easy to bump when pressing the strings around it. And bumping it even 1 mm out of position can effect the result. So being able to hold it down helps a lot. And that is currently difficult to do.

Anyway, great tool.


Good for neck relief, and action too

(Customer's Reviews)

It took a while to get used to, but now I can hold the guitar in playing position, and accurately meassure both neck relief and action. I prefer it to feeler gauges, and a ruler or string action gauge. It's easy to 'push' a string with a feeler gauge, and reading 64ths on a ruler is harder for me than reading the .001 marks on the gauge.

When using the gauge further up the neck, the notches in the brass base don't line up with the strings. But only one string is being measured, so I just push the other strings around so they fit, without pushing them too far aside that neck tension changes. Just ensure that the string being measured moves freely.

When used at the nut, especially on the treble strings, watch out that the heavy plunger on the gauge doesn't deflect the string, when setting the zero point. There's not that much deflection this close to the nut, but still, it's easy enough to adjust.

Further up the neck, this is the primary issue -- setting the zero point without deflecting the string. With the guitar in playing position, push the plunger so it's obviously deflecting the string. Release it, and set zero maybe .005 further up than where the gauge shows. Then, watching the string carefully (not the gauge), raise the gauge a tiny bit, until the string stops moving. Check it back and forth a couple of times. Set the zero point. I find it's within .001-2 of perfect, and the whole process of measuring relief or action on a string takes no more than 15 seconds. Since 1/64 is ~ .016, even .004+- is a big improvement.


clumsy and inaccurate (not me, the gauge)

(Customer's Reviews)

Over the years, I've bought many tools from StewMac and I'm really happy with most of them. Some, though, just gather dust in my toolbox. This is one of them.

For any setup job to be accurate, you need to have the guitar in playing position. Of course, the nut slotting gauge only stays in place when the guitar's resting on your workbench. So you have to put up with guesswork (horizontal position), or won't have enough hands (vertical position).

Furthermore, I find the measurement to be slightly different with each reading. And worse than that: when I use feeler gauges instead, the difference between the two measurements is substantial, regularly reaching .010"

Instead, I use the Safe Slot Nut Guard or just plain old simple feeler gauges.


Essential Must Have

(Customer's Reviews)

Love this gauge and I've gotten to the point I would hate to be without it. Use it for not only nut measurements, but relief, string height, etc. Seems like they should be more durable, or at least fixable. But again, this is my go-to for setups and adjustments. Love it!


Nut slotting gauge

(Customer's Reviews)

This gauge makes the job so much easier. I have found that pushing down on the stem works well with repeatable results.

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