I purchased a toolkit specifically designed for guitars, and beside the tools I expected, it contained this: thickness measurement tool

The description lists it as a thickness measurement tool. What thickness would one measure with this on a guitar? Distance between strings and fretboard?

Googling only gave me results about building guitars from scratch, but the rest of the toolkit is basic stuff like Allen keys and a string winder, so I assume there is some more regular use of that tool.

2 Answers 2


Those are called “feeler gauges” and can measure all kinds of things. Distance between strings and the fingerboard or the frets is one common use for them. I just used my set yesterday to measure string height at the nut. Another likely place to use them would be string height above a pickup. You could also measure the height of a floating tremolo bridge above the body.

If you’re building a guitar, you might want to measure gaps between parts and other small spaces like that.

  • With strings above a pup likely to be 2-3mm, you may need a couple of these sets of feeler gauges! My answer from yesterday never landed. Also be aware that feeler gauges come in two distinct sets - metric (as shown) and imperial - in 'thous' - thousands of an inch. Which is how most strings are considered, coming from the States. Not that feeler gauges are any good for measuring strings - I use a set of caliper gauges. - in 1/1000".
    – Tim
    Dec 30, 2018 at 9:28

This is for measuring the thickness of the nut slot.

  • Oh, I didn't even know the nut was usually a part that would need maintenance, as the one on my guitar is made of metal, so no cutting in. Interesting.
    – crater2150
    Dec 29, 2018 at 21:18
  • @crater2150 - should you consider fitting heavier gauge strings, it may be necessary to do a spot of nut cutting. Zero fretted guitars obviate that problem, if the slots are wide enough anyway.
    – Tim
    Dec 30, 2018 at 9:31

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