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.

Read more


Item # 0670
In stock, ready to ship!




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


Total: $0.00
Quantity: 20


String Action Gauge

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

Subscribe to StewMac's channel on


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

My First Setup

By Len from Texas
(Customer's Reviews) Sunday, January 20, 2013

I've had my Strat for about 18 years, and it has never had any attention. But lately I've been playing it every day, so I started tinkering with it. After fixing the intonation by adjusting the string length at the bridge, I felt encouraged to read more about doing a full setup. I made a slight change to the truss rod, and then set the bridge to standard height. Then it was time to set the string height. None of my rulers was accurate enough, and on some of them, the scale did not start at the edge of the tool.

I ordered a String Action Gauge calibrated in inches. It arrived in just a couple of days, right before Christmas. I set the string height by adjusting the saddles on the bridge. The scale of the String Action Gauge starts right at the edge of the tool, so I set it right on the frets and held it with one hand while turning the Allen wrench with the other hand. The markings on the gauge are bold enough to read easily.

I also set the pickup height for all 3 pickups. I had to do it twice, because the first time I didn't hold the string down at the last fret. The sound was like listening through a cardboard tube. My second try turned out much better.

The setup manual at the Fender website was all in inches, so I didn't have to do any conversions. I'm pretty sure that I will need the metric version of this tool someday. It's probably just a matter of time.

Should have bought one ages ago

By Lance Link from Japan
(Customer's Reviews) Wednesday, January 16, 2013

In general, if you are setting up your own guitar, you should have a string action gauge. I've been going without one for decades, and while "feel" is of course the most important aspect of action, it's really nice to have an objective reference point to know mathematically where your action really falls and whether or not it really has become worse when you instinctively feel like it has. Specifically, this StewMac gauge is exactly what you'd expect it to be, a precise and sturdy metal gauge, in a convenient size, with a lot of info available on all its edges. It can be a little hard on the thicker strings to read where your action lies, but that's going to be the case with any gauge due to the small increments you're working with. I use mine a LOT, especially as here in Japan, in an old-style Japanese house, the climate in my music room changes drastically and I'm adjusting the action almost weekly.

Cool Tool!

By LDT from Southaven, MS
(Customer's Reviews) Wednesday, January 16, 2013

Makes set up a snap!

Great Product!!

By Matan from Dimona, ISR
(Customer's Reviews) Saturday, January 05, 2013

Accurate and Small Great for Setup Work!

Great item and a time saver 

By sofislele from Athens, Greece
(Customer's Reviews) Saturday, December 29, 2012

I got this one in metric and the setup now seems like a game. Great accuracy.

A great tool to have

By J K Jones from Los Angeles, CA
(Customer's Reviews) Wednesday, December 26, 2012

As I start to do more of my own setups, this is a great help.

In constant use

By Reid Hall from New York City
(Customer's Reviews) Tuesday, November 13, 2012

These things got used so much I have to keep two around.

Handy piece of kit

By KC Sligo from Ireland
(Customer's Reviews) Saturday, November 03, 2012

Love this gadget and it is much easier to read than those small rulers

One very handy little tool

By Will Hirsch from Arcata, CA
(Customer's Reviews) Wednesday, October 24, 2012

Like many folks, I suspect, I made do with a pocket rule or sometimes even strings of differing gauges when doing setup work. I finally broke down and treated myself. It really does work better, has lots of different scales with which to measure and works great. Wish I'd just gotten it years ago.

This is a must have

By billmcalister from UK
(Customer's Reviews) Thursday, October 04, 2012

This gauge means that you can check your string action height with a quick glance. Brilliant.

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

Shown on page 16 of our latest catalog.