Acoustic Steel String Guitar Action Gauge

The most reliable way of measuring the action of a guitar is to compare the height of the string to something of known height which is also sitting on the frets. This aluminium action gauge allows you to do this visually without touching the string or the gauge.
This gauge is intended for use on Steel Strung Acoustic Guitars with an action measurement range of 1.3mm to 3.0mm.
We also sell action gauges for Electric Guitars and Classical Guitars - please see the Action Gauge section.

Features
Light passing through (transmitted light) the little gap below the string and above the gauge lets you accurately determine which step on the gauge is the same height as the action - then you read of the action in mm from the gauge calibration.

Using transmitted light in this way gives a high level of optical contrast, and results in a sensitive and reproducible method of measuring such small distances.
The gauge is a thick aluminium sheet with steps milled in it that are 0.1mm lower each step. Each step is 5mm long. These steps provide a very accurate visual height reference that can be placed anywhere on the fretboard.
The action gauge is 4mm by 100mm and stepped in 0.1mm increments and comes in a wooden beech case.
A small handle has been milled on each end of the gauge so the the gauge can be positioned by either hand when the guitar is in normal playing position.
Alternatively with the guitar laid down horizontally the gauge can rest on the guitar fretboard without to support it by hand - this means you can carefully and adjust the gauge position and carefully judge the action without having to hold anything in position. An advantage as then you cannot possibly change the string position by accidentally touching it.

12th Fret Action
A typical use is to place the gauge behind the lowE string at the 12th fret and slide the gauge along so its height matches the string height then you have a direct measurement of the action at the 12th fret. For Steel Strung Acoustic guitars this is typcially 2.3mm for lowE and 1.8mm for high E. The gauge covers these regions of height in 0.1mm increments and so offers a very precise way of assessing the action. The total range of the gauge is 1.3mm to 3.0mm.