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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Quantity: 20


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
Displaying 1 of 16 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Write a review

Why did I wait so long

By Walter N. from Las Vegas, NV 
(Customer's Reviews) Sunday, November 02, 2014

The string action gauge makes setup a snap, I had seen them on "Luthier setup tool reviews" but I made excuses oh I'll order one next week, I should have ordered it a year ago. Great job Stew-Mac, what an awesome measuring tool.

A must have, luthier or musician.

By Trybass from Greece
(Customer's Reviews) Monday, June 09, 2014

Great idea, it acurately mesures and it converts. Bravo.


By Alex D from Saint-Petersburg, Russia
(Customer's Reviews) Tuesday, May 27, 2014

Very accurate, useful tool.

Thanks for having these in metric!

By justinarts from West Texas, USA
(Customer's Reviews) Sunday, May 04, 2014

I have both the inch version and the metric version of this great tool! Really great and easy to use!

A must have

By Ralph's Guitar Service from Sandpoint, ID USA
(Customer's Reviews) Wednesday, April 23, 2014

I was impressed with the String Action Gauge I recently purchased from Stewmac. In the past most of my setups have been done by eye and ear. This takes the guesswork out of it. I have done six setups since getting this handy tool. All were faster, easier, and better than ever before. I don't know how I got along without it.

String Action Gauge

By JPR from Smithtown, NY
(Customer's Reviews) Thursday, April 03, 2014

Great little tool. Very useful and serves multiple functions. However, you need good lighting and (for me) a magnifying lens or glasses to see some of the lines.

Perfect title for a perfect tool

By What a BIG Help. from Jax, FL.
(Customer's Reviews) Sunday, March 30, 2014

I consider myself fairly picky about the string action on my own guitars. Thanks for helping me put my money where my mouth is.

Handy as a Swiss Army Knife

By Lee Gerstenberger from Niles, IL
(Customer's Reviews) Tuesday, February 25, 2014

This tool is a must for setup work. I got this handy gauge about a year ago. I wouldn't try to setup a guitar with out one of these little gems. Worth every penny.

String Action Gauge

By Martin from Rosario, Santa Fe, Argentina
(Customer's Reviews) Thursday, January 09, 2014

with this tool I can make quick and accurate measurements allowing me to make more accurate setups

A great tool to have in the box

By Broian from Tampa
(Customer's Reviews) Thursday, January 02, 2014

This is a great tool to have around. I have several guitars that all feel a little different, a good thing in some cases but in others not so much. Forgive me for wanting both my SG's to feel alike. Enter the string action gauge. The slight different in string height is no longer an issue.

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