Using a Digital Caliper to Measure String Gauge

[sweiss]

Originally Posted by flaggerphil

Why? I don't get it.

The same question popped into my head as well. What's the point? Are you going to discard strings that are .0000001 out of spec?

The info on the package is close enough for me. It ain't rocket surgery.

[devellis]

Again, it's not how many decimal points the read-out goes to, it's the reproducibility of the values you get. Some inexpensive digital calipers are better than others, with some not giving consistent values to the third decimal place over successive readings. That makes it hard to be sure a string is a .012 and not a .013. Even cheap micrometers will give consistent readings beyond the 4th decimal place. Digital ones are fare more convenient than the old, analog ones with a vernier scale. Unless you're used to reading the latter, it can be pretty confusing and the packaged directions aren't often a lot of help. As inexpensive as digital micrometers have become, they're worth having if you like to mix strings from multiple sets or want to determine what set of strings are on a guitar that you're not familiar with. For just determining which string is the E and which is the B, calipers are fine. Even if not super-precise, one should consistently yield a higher value than the other. For differentiating a .012 from a .013, on the other hand, some of the cheaper calipers may or may not suffice. And there are medium-light string sets around these days that have .0125 E strings, which would be even harder to differentiate from a standard light or medium E. If, on the other hand, you're measuring the thickness of the wall on a bottleneck slide, calipers are faster, easier, and plenty accurate enough. The thin tip of the caliper will work much better on a curved surface like a slide wall than the disc-shaped pads on a micrometer.

The vast majority of players will never find themselves needing or wanting to measure this stuff, of course. But if for some reason you're doing it, a good caliper (or even a mediocre micrometer, which would likely cost less) is worth having.

[drplayer]

Originally Posted by sweiss

The same question popped into my head as well. What's the point? Are you going to discard strings that are .0000001 out of spec?

The info on the package is close enough for me. It ain't rocket surgery.

That's all good IF you replaced the strings or IF you kept the package, or IF you remember what strings they were. But, if you don't know or have these things, the only way to know what gauge strings you have are to measure them. I don't think the question was posed because someone wanted to verify what the package said.

[Irish Pennant]

Using micrometers or calipers is as much about "feel" as it is about the quality of the tool. Having a gage of a known value to practice on that's near the size and shape that you want to measure will teach you the "feel". Measuring near the tips of the caliper will yield a different measurement than farther in. Try to be consistent in placement and applied force when measuring.

To touchup clean the measuring surface of the calipers, while measuring the thickness of a clean piece of paper, slide the paper.

[sweiss]

Originally Posted by drplayer

That's all good IF you replaced the strings or IF you kept the package, or IF you remember what strings they were. But, if you don't know or have these things, the only way to know what gauge strings you have are to measure them. I don't think the question was posed because someone wanted to verify what the package said.

The OP hasn't said why he wants to measure his strings, so we don't know. That's why I asked.

I guess I assume, perhaps mistakenly, that most folks know what their guitars are strung with.

[Pitar]

Originally Posted by jw3571

Per some recommendations here I bought a digital caliper to measure string gauge? My problem is i'm not getting in the right ballpark for measurements. What's the trick with these? Is string gauge in inches?

A 0-6 inch digital caliper has 3 significant digits to the right of the decimal so there's plenty of accuracy for measuring string gauges. The problem you'll encounter is that seldom do the strings accurately represent their advertized diameters. They're usually off enough to raise the question about truth in advertizing.

I did this exercise many years ago across several brands and came to the conclusion that one wire maker was making the core wires for the all brands I checked, evidenced by identical variances in like cores gauges, meaning the extrusion dies were common to them. The dies wear out (get larger) and the core wires follow suit. Turns out I was right. Only one wire maker supplied the various brands I checked out.

Anyway, a regular 6-inch caliper with 3 significant digits is accurate enough.

[DanPanther]

Maybe it should be clarified if you are referring to straight micrometers, ( Like Stated ), or are you talking about 4 digit, or dial micrometers. A big difference in reading the results. Micrometers do not have digital or analog readouts on them.

Dan

[Tom West]

Originally Posted by duane v

I only use calipers for reference or non critical measurements.... I worked in a 17025 calibration lab for many years, and now I design torque instruments for Snap-on Tools.... All our QA personnel are not allowed to use calipers for measuring O.D. call outs that measure 3 inches or less.... Everything in the design phase must meet the k=2 confidence level..... Now for guitar strings....lol... Just use the package or the calibrated eye....

This is not space ship work....................just a couple of guitar strings.
Tom

[Silly Moustache]

I have a micrometer in my "guitar" tool box - I got it recently in a junk shop- It's a good old British made Moore & Wright.

The most useful measuring tools I have are a set of feeler gauges and a Stewmac Action gauge - or at least it was until I saw another Chinese made version which is actually easier to read.

[duane v]

Originally Posted by Tom West

This is not space ship work....................just a couple of guitar strings.
Tom

That's why i stated just use your friggin eyeballs.... In my 40 years of playing guitar I never had to use a measuring instrument to measure strings.... Even at the age of 7 when I did my first string change

[Howard Klepper]

One of the most often used tools in my shop is a pocket dial thickness gauge. I have two of them, actually--one stays at the bench, the other at the thickness sander.

Since getting one, I rarely have use for a micrometer.

I mistrust cheap precision measuring tools. Sounds too oxymoronic. In particular I mistrust cheap tools with digital or dial readouts. They add layers for potential inaccuracy over a vernier readout.

You need to read string gauge between two flat anvils if you are not ballparking.