Feeler gauges for measuring string height question

[RickPick]

I bought a set of automotive feeler gauges recently to use in learning how to adjust the action on my mandolin. I have an old beater mandolin I purchased to practice on, and Rob Meldrun's (sp?) ebook about how to set up a mandolin. Today, I thought I'd take some practice measurements on my Weber, which is set up just the way I like it. I was surprised to realize what a range of heights I could get between the same string and the same fret! When you measure, should there be ANY snugness between the two? Should the gauge TOUCH both the string and the fret? I'd say I could use 5 or 6 different thicknesses of feeler gauges at the same spot, and not be sure which one was the measurement I wanted!!!! Any advice about what I should be doing? Sliding the gauge from below the fret and toward the nut? Sliding it inward from the outside of the neck? LOOKING instead of FEELING? (They are called feeler gauges after all, and my eye sight ain't what it used to be.....) Your guidance would be most welcome.

[Stevo75]

Do you have a radius fretboard? That makes it trickier because you'd have to bend around the frets, so to speak.

You should be able to narrow it down to one or maybe two thicknesses. Just put it under one of the two strings (if you have a radius board). It should just touch the string, but not push it up. You can fit more feeler gauges under the string than is correct because you're allowing the string to move up slightly. Know what I mean?

[Ivan Kelsall]

I've recently done just that with my Weber mandolin,checked the string height at the 12th fret using feeler gauges. The gauge blade combination should just touch the underside of the string without lifting it. Only ONE combination of gauge blades will be correct. It's easy to tell if the combo. is too thick,the strings seem to clamp down on them. The blades should slide easily between the fret & the strings,
Ivan

[Bill Kammerzell]

I bought a set of automotive feeler gauges recently to use in learning how to adjust the action on my mandolin. I have an old beater mandolin I purchased to practice on, and Rob Meldrun's (sp?) ebook about how to set up a mandolin. Today, I thought I'd take some practice measurements on my Weber, which is set up just the way I like it. I was surprised to realize what a range of heights I could get between the same string and the same fret! When you measure, should there be ANY snugness between the two? Should the gauge TOUCH both the string and the fret? I'd say I could use 5 or 6 different thicknesses of feeler gauges at the same spot, and not be sure which one was the measurement I wanted!!!! Any advice about what I should be doing? Sliding the gauge from below the fret and toward the nut? Sliding it inward from the outside of the neck? LOOKING instead of FEELING? (They are called feeler gauges after all, and my eye sight ain't what it used to be.....) Your guidance would be most welcome.

I slide it inward from outside the neck. You'll see the strings move if the gauges are too thick. I understand what you mean about "feeler" but you still have to look. When you use them on a spark plug the electrodes don't move. I also use the same gauges to check the neck relief. I Capo the strings at the 1st fret and hold the other end down at the 12th. Then I take a feeler measurement at the 6th.

[violinvic]

I use a 6" Starrett scale graduated down to 64ths and a pair of cheap magnifying glasses. Got feelers, too. But don't use them for setups.

[Soupy1957]

Do you have a radius fretboard? ................

Another excellent reason to buy a flat fingerboard mandolin, and not one that is radiused!!

[Willie Poole]

The bridge and nut are also radiused so there shouldn`t be a problem...just so the feeler gauge just barely touches both the string and the fret without pushing the string up is the way I do it...I just don`t think a 64th of an inch matters too much...

Willie

[CarlM]

The only important thing is how the mandolin plays, not how it measures. The measurements are a guide to get it in the right ballpark. Also if it measures right on and still buzzes or plays hard it is an indication something else is wrong, like high frets or neck relief. Feeler gauges take some experience and if you have not worked in a craft type of job they take some getting used to. You need to look as well as feel despite the name, especially with soft or flexible surfaces like the strings..

[RickPick]

Many thanks for all the information and suggestions. It will be very useful. I was quite surprised about what I didn't know when I first stuck those feeler gauges in! I had intended to make a quick measurement on my Weber before I changed the strings, something I could then use for future reference. But the beast quickly became more complicated than I had anticipated. Your input will help, as always. Thanks a bunch.

[Mandoplumb]

Willie something flat (feeler gauge) laid on something arched (fret) will only be accurate at the point it touches. Maybe a fret doesn't have enough arch to make a noticeable difference, maybe it does, I don't know but there will be some inaccuratcy. Also if touching on one side and "reading" on the other there could be a bigger difference.

[John Morton]

The problem with feeler gauges is that they must be held perfectly parallel to the string and perfectly tangent to the fret. A better choice is a wire gauge, e.g. a piece of (unwound) piano wire. As RickPick points out, contact is very difficult to detect and requires strong magnification to confirm small movements of the string. "Feeling" doesn't work for this - feelers are typically used to poke into small cracks between solid surfaces.

Once you have enough magnification to see the gap and the gauge reliably, you are at the point where you can resolve the graduations of a fine measuring scale. You need to view from the side, to get an elevation view of the gap. My favorite scale is a Starrett C607R-6, satin chrome for visibility, with 1/100ths "aircraft" graduations. That model also features 1/64ths, if you like that sort of thing. (Thanks Paul Hostetter for the closeup.)

http://www.starrett.com/metrology/pr...-Rules/C607R-6

[Mike Arakelian]

When I use my feeler gauges I try to feel just the very slightest bit of resistance when sliding the gauge between the bottom of the strings and the top of the frets. 1 or 2 millimeters or 1/64” isn’t going to make much difference one way or another. It’s not unusual for me to make minor unmeasured adjustments on the string height from time to time. I keep a simple log recording the heights on both the treble and bass sides each time I use the gauges. This gives me the freedom to play with the set up as I always have a reference to go back to if I mess things up.

[mandolin breeze]

Some time ago I started using a penny at the 12th fret on both the G and E strings. A penny is 1.52 mm thick. I find this a very comfortable height and is high enough to give the mando some real bark. I set the string so that the penny is touching, but not lifting the string. Really a super simple method to set all my instruments consistent and identical. And, there is always a perfect "string height gauge" available anywhere.

[Bernie Daniel]

Some time ago I started using a penny at the 12th fret on both the G and E strings. A penny is 1.52 mm thick. I find this a very comfortable height and is high enough to give the mando some real bark. I set the string so that the penny is touching, but not lifting the string. Really a super simple method to set all my instruments consistent and identical. And, there is always a perfect "string height gauge" available anywhere.

Some time ago when my son was in H.S. I had he and his friend measure the thickness of 100 new pennies and to get data for doing basic statistics. As I recall the mean for the new pennies was 1.43 mm and the range was bigger then one might think something like 1.35 to 1.57 mm. But your point is a good one. You can measure something like a coin and then you have something handier then getting out feeler gauges.

A Stew-Mac string action ruler is the method I prefer much faster.

[pops1]

I like the E string much lower than the G string. It doesn't need to be as high and plays easier when it is not. I measure with a ruler with measurements on the end so it lays across several frets and can't tip and the measurement is accurate. I also have made and aluminum gauge with lines scribed in the same as the ruler 32" and carry it with me for on the go measurements. I can check and adjust anywhere. I also carry several tools to adjust the saddle under tension. Some thinner than others depending summer or winter and how high/low it is. I may be a little far gone, but I like a low action and want it consistent.

[CarlM]

I will try to not go too far off in the weeds about measurement here but will again reiterate that how the instrument plays is the goal not achieving a certain measurement.

All the issues with feeler gauges apply to ruler measurements. The line of sight can make a major difference in the reading as well as how straight the ruler is held. Aligning the mark with the bottom of the string and top of the fret is a feat in itself.

To test how good your measurement is, repeat your measurement on the same instrument ten times, writing it down and starting fresh each time. Ideally have a couple of other people do it and trade back and forth each repetition so you can kind of forget what you measured before. There are formal statistical approaches called repeatability and reproducibility studies using standard error treatments.

Feeler gauges, rulers or any other instruments require so care and technique to use keeping them square to the items being measured and getting a consistent feel. This is multiplied with flexible items like strings.

[Bill Kammerzell]

For me, as long as I'm careful and precise, I come up with the correct measurement. Worked with precision instruments much of my working career. That doesn't make it any easier, but I have a certain amount of trust in my own abilities and the accuracy of using instruments correctly.

[Willie Poole]

Geeeze, You all make this sound rocket science...I like the idea of using a penny on the E string and a nickel on the G string...GO PLAY IT AND SEE HOW IT SOUNDS...

[Wrnchbndr]

I had a 12" length of 1/4 X 1/4 brass rod that I tapered from one end to the other on a belt sander -- took a while because I had to cool it off every 10 seconds and then I polished it to a mirror finish. Over the length of 12" it goes from .010 to .25". I used a set of calipers to scribe marks at ten thousandth intervals. If you need to measure string height, its very good for this. I don't measure anything when doing a set up.