Guitar action measuring tool for (cheap) digital dial gauge

After oogling over the professional tools for this purpose, I decided I could develop a 3d printed model to achieve the same purpose for a fraction of the cost. This is an electric guitar string action gauge block. It holds a digital dial gauge in a position that allows you to accurately measure the height of the strings in relation to the fret. This is used to support adjusting action to the player's preference or requirements.

By all means, if you can afford it, buy the professional stewmac or crimson guitars tools instead!! They are excellent!

If you'd rather try the homebrew approach instead - print this block, find a cheap digital dial gauge on the Internet, make it as light as possible (see below) and start measuring! It's important that the gauge is digital for the opportunity to reset to 0 before taking a measurement.

Adding lightness - The problem with dial gauges

The major problem with this kind of setup is the weight of the plunger of the indicator which pushes the string down, thus affecting the measurement (not unlike the pro tools, which I'm sure have been lightened too for this purpose). This can be countered significantly (but not totally) by:

• removing the plunger tip (it just unscrews)

• opening the back of the indicator and releasing/removing the spring that pulls the plunger back to its fully extended position (this makes the most difference).

It is still not perfect and you can see the string deforms a bit with the plunger's weight. You can work out this measure and add to your measurement, but you need to do this individually on all strings because all are different, have different tensions and are moved varying amounts by the plunger.

Printing

The model prints well at standard quality 0.20mm layer height, it doesn't need much strength of precision. The bottom part needs to be clean and rounded, so may need a bit of cleaning up regardless of using supports. The tolerance of the model is set for PETG, it may be slightly loose for PLA, but it matters little because the clamping method clears this gap and holds the gauge securely.

Assembly - Holding the dial gauge in place

The tool requires two M3 screws and nuts to clamp the body of the dial gauge. It needs little pressure but should clamp the gauge in a way that it doesn't move out of the tool.

How to use (see pictures)

• set the tool on the guitar with the wide cut over the fret and the narrow cuts over the strings. the dial gauge plunger should touch the string it is measuring

• set dial gauge to 0

• push the plunger until the string touches the fret

• take your measurement (you can see, on my poorly setup guitar, the high E is at 1.47mm, the D at 1.81mm and the low E is at 2.2mm)