Nut Slotting Gauge

  • 67 Reviews
  • Write a review

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

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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
In stock, ready to ship!


Total: $0.00
Quantity: 20


Nut Slotting Gauge

Dan Erlewine uses the Nut Slotting Gauge: the most accurate measure of nut slot depth.

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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! Newsletter

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.

Ratings & Reviews

Nut Slotting Gauge

  • Based on 67 Reviews
Displaying 1 of 7 1 2 3 4 5 6 7
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Great Tool

By JMW from Biggleswade, UK
(Customer's Reviews) Wednesday, January 14, 2015

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

By DeeCee from NY
(Customer's Reviews) Thursday, December 25, 2014

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

By Jeffrey Hawkins from Hood River, OR 
(Customer's Reviews) Thursday, November 20, 2014

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

By Moosie from CT
(Customer's Reviews) Monday, November 17, 2014

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)

By Marc Terreur - Marcus Gtrs & Basses from Sint-Niklaas, Belgium
(Customer's Reviews) Friday, August 08, 2014

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

By Tim Nolte from Chesapeake Beach, MD
(Customer's Reviews) Wednesday, February 12, 2014

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

By Jas from Florida
(Customer's Reviews) Friday, January 17, 2014

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

Easy enough, even for a Novice

By Tmc from Trinity Ala
(Customer's Reviews) Sunday, January 12, 2014

I'm a Novice repairman, not in any way a professional repairman, that I know comes with years of experience, but this device makes it easy enough that even I can set the nut the way I want it..with more accuracy,, a lot easier than feeler guages.. Good Product

Good tool

By Fredpistacchio from Sparks, NV
(Customer's Reviews) Friday, November 22, 2013

It's a good tool

Nut Slotting Guage

By Simon K from Darwin NT Australia
(Customer's Reviews) Friday, November 15, 2013

I tried to use my nut slotting gauge to file the nut slots on my Strat to the correct depth, one thing I noticed was that the accuracy was a bit out, I discovered this by using the gauge to file a string slot so that there was 0.018" clearance between the top of the first fret and the string, then I used a 0.018"-thick feeler gauge blade to check, the string clearance was actually more than the feeler gauge, as far as I knew, I was using the nut slotting gauge correctly, also the dial being marked back-to-front makes it hard to read so you need to do some mental gymnastics to interpret the reading.

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