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Oct 5, 2022 - 2:04:52 PM
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5322 posts since 1/5/2005

Someone asked how to go about measuring string action recently and it reminded me of the little gizmo I made years ago. I had a small piece of hardwood kicking around that begged to be put to use. I sanded a taper to it and it ended up to be 1.5 mm thick at the one and 6 mm at the other.

The thickness measure are not really important but the steeper the slope, the closer the thickness measure stripes will be. I use millimeters for measuring stuff like that but there's nothing to stop you from using fraction inches or even thous, whatever turns you on.

Start at at thickness measure number you're comfortable with, I decided on 2 mm. Set your calipers at 2 mm and lock it in place with the tightening screw. As shown on the picture, slide the caliper opening along the wood until it pinches and mark the contact spot with a pencil, sharpie or whatever.

Repeat doing this in increments of 1/10 mm and you're done. As you can see on the pic, there's a nice distance between the marks so it's actually pretty darn accurate.

When done, shove the stick between the top of the 12th fret until it pinches at the bottom of the string and there's your magic action number.

Don't have a piece of wood? Go treat yourself on 3 popsicles and glue the leftover sticks together smiley

Heads up to patent hunters: this writing and the pictures are copyrighted by yours truly...

Oct 5, 2022 - 5:31:14 PM
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10134 posts since 8/28/2013

In the time it would take me to make one of thses, I could measure a couple dozen actions with my six inch scale. Also, I have had need in the past to measure the height of the inner strings, and if this device got pinched by the outside strings, that couldn't be done.

Oct 5, 2022 - 5:44:49 PM
Players Union Member



16060 posts since 8/30/2006

I like it

Oct 5, 2022 - 6:26:42 PM

13688 posts since 6/2/2008

This type of gauge is easy to use. Available for a few dollars on eBay, $10 on Amazon and elsewhere, $28 from Stew-Mac. A real cheapie I bought on eBay long ago was mis-printed. The image was enlarged, so all the measurements were wrong.

Oct 5, 2022 - 6:36:59 PM

2158 posts since 11/17/2018

Originally posted by Old Hickory

This type of gauge is easy to use. Available for a few dollars on eBay, $10 on Amazon and elsewhere, $28 from Stew-Mac. A real cheapie I bought on eBay long ago was mis-printed. The image was enlarged, so all the measurements were wrong.


I bought one from Stew-Mac several years ago, and it is a handy tool.

Oct 5, 2022 - 6:48:22 PM

7219 posts since 9/21/2007

This is a good idea.

Oct 5, 2022 - 7:32:12 PM
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Alex Z


4992 posts since 12/7/2006

Pure genius, Mr. Bart.

One of the main advantages of Mr. Bart's device is accuracy and precision, accuracy and precision independent of visual perspective.

Peeking at that 6 inch ruler?  Is that a shadow or a line that I see?  How wide is the line on the ruler -- is that as precise as can be measured? I'd put the precision of a ruler at about 0.5/64", or roughly .008", assuming the end of the ruler has been cut exactly perfect from the first line.

For the rectangle gauge, still the same issue of visual perspective, and the cutting of the edge from the first line.

And if you're measuring on a radiused fingerboard such as a guitar, you get a different measurement depending on which side of the string the device is on.

With Mr. Bart's invention, doesn't matter whether the fingerboard is flat or radiused.  And don't have to peek in the shadow of the bottom of the string to see where that horizontal line crosses the measuring device.

The ruler and rectangular gauge are pretty good for relative changes, such as "I tightened the head a tiny bit and want to see what that did to the action height."  Or "what is the incremental change in action height as I go from 6th string to 5th string etc. to 1st string on my guitar."

One of those "why didn't I think of that" inventions!  Stew-Mac might be selling metal ones for $50 in a couple of years.  Hope Mr. Bart gets the royalties.  smiley

Edited by - Alex Z on 10/05/2022 19:47:29

Oct 5, 2022 - 8:28:20 PM



66978 posts since 10/5/2013

You guys measure string height…? Sheesh
Watch at 4:18youtu.be/JFrMXMuql0Q

Edited by - chuckv97 on 10/05/2022 20:30:06

Oct 5, 2022 - 9:23:18 PM

Bart Veerman


5322 posts since 1/5/2005


@G Edward Porgie wrote: "if this device got pinched by the outside strings, that couldn't be done" >>>  the outer string(s) being pinched doesn't mean the gizmo is stuck and they won't mind if you keep pushing it farther to measure the inner string(s)

@Alex Z >>> you're making me blush...

One improvement I never got around to doing: the gizmo slithers off the fret kinda easily so if you widen it a bit and glue a strip on the bottom of it a 1/4 inch away (kinda like an out rigger canoe) from the fret then it'll become nice and stable. A flat tooth pick, with it's thickness being roughly the same height of yer typical fret, ought to do it.

For the fraction-inch fans: provided your set of calipers has the fraction feature, you can mark the stripes at 1/64s to get to the "standard" 7/64" (2.8 mm) action.

By the way, this gizmo don't take batteries but it's digital device nevertheless as you need your digits to operate it wink

Yup, there's other ways but this one's cheap enough.

Oct 6, 2022 - 7:55:01 AM
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Alex Z


4992 posts since 12/7/2006

For precise measurement you have to know exactly where both sides of the gap lie.  The difficulty with the 6-inch ruler and the rectangular gauge is (a) don't know if the edge has been cut precisely relative to the first measuring line on the device, (b) you're trying to eyeball the shadowed part of the bottom of a string compared to the width of a drawn line, and (c) radiused fingerboards are problematic because the string has a width, and the distance to the fret is not the same on both sides of the string.  The devices are useful most of the time, and I use both.

The engineering principle of Mr. Bart's invention is that both sides of the measuring device are known, since they are sized by the calipers.  Same principle as using flat gauges -- no guessing if one side of the flat gauge has been cut correctly relative to the other side.  And, you can see and feel the string touching (or not touching) the top of the device.  

Right now, if I need an accurate absolute, not relative, measurement, I either use a small stack of flat gauges or the solid shaft of a drill bit.  The drill bit works well because it is round and therefore will touch the string only at one point -- difficulty is mine are only in discrete steps of 64th inches.

So nothing wrong with using a ruler or a rectangular gauge or a flat gauge or a drill bit, recognizing their limitations.  But this is a better mousetrap.  smiley

Edited by - Alex Z on 10/06/2022 07:55:30

Oct 6, 2022 - 5:42:45 PM

10134 posts since 8/28/2013

I know all the problems that can arise with a six inch ruler, and 5 decades of using one has taught me how to cope with those.

It's probably okay to keep pushing an outside string out of the way, but it can, over time, force a string groove into the wood of the gauge.

I don't care what others use or think, I've had very good results with my little steel rule and am not about to change. My gauge is high quality, and is not cut crooked. The lines are also narrower than any pencil marks I could make on a wooden wedge, and therefore, probably more accurate.

frets are narrow and a horizontal gauge can rock on those narrow frets. If the gauge rocks,it won't be accurate.

I suppose, with some care, though, problems can be kept to a minimum.

Oct 9, 2022 - 10:47:36 AM
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Alex Z


4992 posts since 12/7/2006

One of the design benefits of the new "wedge" device is that it uses the concept of visual leverage to elongate the measuring points, same concept as a dial caliper.

For example, on the rectangle gauge, the measuring line is spec'd at .005 inch, and thus touted to give the reader an accuracy of .005" depending on which part of the line the string hits.  (The down side is that the measuring line is in the shadow of the string, and the string being round means that the position of the eye is critical to matching the line against the bottom of the string.)

The new wedge device simply expands the measurement readings.  For example, take a 4" wedge that is calibrated between 4/64 and 10/64.  The difference of 6/64" is then spread across 4 inches, or 256/64.  Therefore, each 1/64" of change in string height is about 2/3" apart on the device -- very easy to see, and with a lot more precision than the rectangle gauge.  A .005" line on the rectangle gauge is equivalent to about a 7/64" wide line on the wedge device.  Thus, the accuracy of a line is no longer a limitation on the wedge device, since an easily visible line can be drawn much narrower than 7/64".


The homemade wood device works well.  If one wanted to produce the wedge device commercially, my advice would be:

  -- Make it out of metal rather than wood -- eliminates wear and breakage.

  -- Make it a half cone rather than flat wedge -- thus can touch the string only at one point, eliminating aligning the flat part with the string (one of the downsides of flat auto gauges), and so eliminating the need for the "outrigger" bars.

  -- Put a very shallow groove in the bottom (flat side) of the half cone, so that one can feel the device sitting directly on the fret.

Just because other measuring devices are used and useful doesn't mean that something better cannot be invented!  smiley  Gives another choice, in addition to rectangle gauge, simple ruler, or a stack of flat auto gauges.


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