StewMac String Action Gauge And Ruler, Metric - Precision Setup Tool

In this review the StewMac String Action Gauge and Ruler is evaluated as a focused setup tool for guitar and bass technicians and serious players. The bottom line: it is a compact, well-made measuring tool that speeds routine setups by combining a progressive string height scale with straightforward conversion info, so the single biggest reason to buy is its combination of accuracy and durability for repeatable action readings during setups and repairs.

Key Features

• Lifetime Promise: Backed by StewMac's lifetime support and warranty, the tool is built for long-term use and reliable service life.
• Progressive string height scale: Slide the gauge across frets to read action quickly, making string height checks faster than using a standard ruler.
• Swiss army ruler for techs: Measures string height, saddle slot depth, nut height and pickup polepiece height with pinpoint accuracy for precise adjustments.
• Original StewMac design: Developed by Dan Erlewine and Don MacRostie, the layout is optimized for the common measurements needed in instrument setup workflows.
• Back-side conversion chart: Includes conversion and reference information on the reverse to reduce calculation time during setups.

Who It's For

The gauge is ideal for guitar and bass technicians, luthiers, and experienced players who perform regular setups and value a durable, repeatable measuring reference. Its metric markings and progressive scale suit workshops where quick checks across frets and saddle slots save time.

Less experienced hobbyists who prefer large, high-contrast markings or those who need imperial-only measurements might find the scale harder to read or not aligned with their usual units; in that case a different ruler or a model focused on readability could be a better fit.

Pros & Cons

Pros

• Solid stainless steel construction gives a stiff, durable feel that resists bending during routine shop use.
• Progressive height scale greatly speeds action readings compared with a conventional straight ruler.
• Design and conversion chart reduce setup time by consolidating common measurement tasks on a single tool.

Cons

• Some users report the markings are fine and accurate but not as easy to read in low light or for those who prefer larger numerals.

Specifications

Brand	StewMac
Material	Stainless steel
Measurement system	Metric with conversion chart on back
Primary uses	String height, saddle slot depth, nut height, pickup polepiece height
Design origin	Developed by Dan Erlewine and Don MacRostie at StewMac
Durability promise	Lifetime Promise with expert tech support

Our Verdict

The StewMac String Action Gauge is a practical, durable setup tool that delivers fast, accurate measurements for technicians and players who do their own setups. Its progressive scale and conversion chart make it good value for workshops where speed and repeatability matter, though those who need larger, high-contrast markings should consider alternatives.

Frequently Asked Questions

Is this tool durable enough for professional use?
Yes. The stainless steel construction and StewMac Lifetime Promise make it suitable for regular workshop and tech use.

Can it measure pickup polepiece height as well as string action?
Yes. The ruler is designed to measure string height, nut and saddle slot depth, and polepiece height with precise readings.

Does it include both metric and imperial scales?
The tool is metric with a back-side conversion chart to help convert values quickly; it is not primarily an imperial-only ruler.