String Action Gauge

  • 158 Reviews
  • Write a review

Fast, accurate measurements for setups. Our String Action Gauge is a "Swiss Army Ruler" for setup adjustments on any stringed instrument.

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Item # 0670
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Item # 0670-M
In stock, ready to ship!


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String Action Gauge

Dan Erlewine uses this gauge for checking string height, measuring saddle and pickup heights and more.

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Fast, accurate measurements for setups. Our String Action Gauge is a "Swiss Army Ruler" for setup adjustments on any stringed instrument.

This pocket-size stainless steel rule has become a luthier's favorite in busy shops. It's the best way yet to get vital measurements on acoustic and electric instruments.
• String height
• Bridge saddle height
• Saddle slot depth
• Fret slot depth (unbound fingerboards)
• Nut height
• Pickup polepiece height

No more "three-and-a-half-64ths or 3/32" plus one of those little lines." This gauge measures in ways that regular rulers can't. —Dan Erlewine

Developed here at Stewart-MacDonald by Dan Erlewine and Don MacRostie, the gauge features a progressive string height scale: simply slide it across the frets and read the measurement under the string. It's faster to use than any ruler, and stays parallel to the fingerboard—much easier than trying to hold a ruler perpendicular to a rounded fret. The string height markers are graduated from .010" to .140" on the inch model, and from 0.25mm to 3.50mm on the metric version.

The back of the gauge has a time-saving fractional/decimal/metric conversion chart.

The String Action Gauge is made of durable stainless steel with precision-etched markings, and fits right in your pocket.

Tip: You can use the gauge to set router depth, instead of a shop ruler. It sits solidly on your router base, with the scale right where you need it.

Product Instructions

Making a Nut, Step-by-Step

Dan Erlewine, of Stewart-MacDonald's R&D Team, walks you through making and installing a new nut.

Product Instructions

String Action Gauge

How to determine string action with the String Action Gauge.

Product Instructions

Metric String Action Gauge

How to determine string action with the Metric String Action Gauge.

Ratings & Reviews

String Action Gauge

  • Based on 158 Reviews
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Like me... you might have thought your ruler is good enough...

By Jedidiah Guitars from Canada
(Customer's Reviews) Friday, May 03, 2013

One day I took the time to measure my ruler with a verneer caliper and discovered that it was extremely inaccurate for measuring string height. So I finally splurged and bought this tool. IT'S AMAZING! I DON'T KNOW HOW I LIVED WITHOUT IT. Not only is it accurate, it's soooooo thoughtfully designed, and user friendly that it improves my productivity noticeably! This tool paid for itself many times over the first time I used it!

String Action Gauge...

By DaVinci Luthiers from Oakville, Ontario, Canada
(Customer's Reviews) Wednesday, April 24, 2013

This is a very useful tool to use, prior to setting the under-string radius at the bridge. I use this as a starting point when setting up the height of both E strings, then use the string gauge radius tool to adjust the A,D,G,B strings accordingly... I always fine tune after the height and radius have been set... I would highly recommend this tool, especially if you are doing a lot of set ups...


By n17r0uS from Almaty, KZ
(Customer's Reviews) Monday, April 01, 2013

Must have tool and that's all I can say.

A Nifty Tool!

By DJB from USA
(Customer's Reviews) Sunday, March 31, 2013

Because of this tool I don't dread doing a full set up of my guitar anymore!

A must have

By Tim Skau from Norway
(Customer's Reviews) Monday, March 18, 2013

This is one of the tools I use the most. Great value, and highly recommended.

Best thing since sliced bread - OK, actually better!

By Frank Levine from Los Angeles, CA
(Customer's Reviews) Sunday, March 10, 2013

I've always sort of 'eyeballed' my string action. And i always ended up with a lot of buzzing because i got it too low or aching fingers because i got it too high. For the first time since I've been playing guitar and doing my own adjustments i got it right the first time. I found some 'suggested' string heights for my Strat and with the combination of the String Action Guide and the Under String Radius Gauges my Strat is playing like I never believed possible. If you're gonna do your own setups - you NEED this handy little tool. If you have a Fender guitar you also need the understring radius guides to help you set the bridge pieces - but that's another review entirely. These guys at StewMac think of EVERYTHING!!

Easy action check!

By Lennie from Madrid, Spain
(Customer's Reviews) Thursday, March 07, 2013

Thanks a million. After 40-odd years of fiddling with feeler gauges and rulers stood on end etc you have simplified my measuring of string action. Coulda done with thinkers like you guys many years ago! Congratulations.


By Sea Level Sound from Portsmouth, RI
(Customer's Reviews) Wednesday, February 27, 2013

This little tool makes setting up any guitar a piece of cake. The conversion table on the back is a lifesaver. Indispensable!


By Twan from The Netherlands
(Customer's Reviews) Sunday, February 24, 2013

Brilliant tool! The progressive string height scale is great. Set up all my guitars in no time.

Great Product Period

By RockinRonnie from Ontario
(Customer's Reviews) Saturday, February 09, 2013

Bought one of these as I wanted to start tinkering with my own guitars. Product is awesome. I had a small mechanical ruler, but this is sooo much easier and accurate. Pricey perhaps, but worth every penny. If you want to set up guitars, you should buy one of these.

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Shown on page 16 of our latest catalog.