How to measure the guitar's scale length

drmlyung
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How to measure the guitar's scale length

Post by drmlyung » Fri Jan 27, 2017 5:35 am

From what I understand, the guitar's scale is the measurement from middle of the nut edge(fret board side) to the middle of the saddle edge(sound hole side),

So I try to measure my Yamaha GC10S' scale in two ways,

1. Middle of the nut edge(fretboard side) to the middle of the saddle edge (sound hole side), ruler starting point at 10cm, ending at 76.2cm -- scale - 662mm

2. Middle of the nut edge(fretboard side) to middle of 12th fret edge(nut side)
ruler startinpoint at 10cm, ending at 43.0cm + 12fret width 2mm + middle of 12th edge(sound hole side) to the middle of the saddle edge(sound hole side) starting at 10cm, ending at 43.0cm ==>> 330mm +2mm +330mm = scale 662mm

The above measurement results matched the official Yamaha's archive data.

But, is this the correct way to measure a guitar's scale? :?:

Please enlighten me.

vesa
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Re: How to measure the guitar's scale length

Post by vesa » Fri Jan 27, 2017 6:48 am

From the nut to the 12th fret X 2, the ruler placed on the fretboard.
12th fret is in the middle that is why times two.
The measurement from the nut to the saddle is the compensated string length,
which is longer than the actual scale length.
Vesa Kuokkanen

Antonio Marin nr. 813 1995 (Bouchet)
Vesa Kuokkanen 2016

drmlyung
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Re: How to measure the guitar's scale length

Post by drmlyung » Fri Jan 27, 2017 7:12 am

vesa wrote:From the nut to the 12th fret X 2, the ruler placed on the fretboard.
12th fret is in the middle that is why times two.
The measurement from the nut to the saddle is the compensated string length,
which is longer than the actual scale length.
how to take into account of the width of the 12th fret? middle of the 12th fret?

Anyway, I did measure a number of guitars from different makes/luthiers, the scale length data seems to match the results from the measurement methods of my initial post.

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Beowulf
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Re: How to measure the guitar's scale length

Post by Beowulf » Fri Jan 27, 2017 1:44 pm

My 1971 Yamaha GC-10 measures 662mm from the front edge of the nut to the middle of the saddle for both the 1st and the 6th strings. The saddle is not compensated except for the 3rd string which is cut back at the saddle ~ 1mm. Thus the scale is exactly 662mm for the 3rd string as the saddle compensation is right to the centre of the saddle. This suggests that the actual scale for the other strings is ~ 661mm as those strings leave the saddle at the front edge. The actual "playing" length may be slightly greater as the string is not locked at the nut and saddle and will vibrate behind the leading edges, particularly when played hard. In addition, lower action and longer scale guitars require less compensation as the strings do not stretch as much when fretted.
1971 Yamaha GC-10 (Hideyuki Ezaki)
2017 Yamaha GC82S (Akio Naniki/Naohiro Kawashima)

JohnB
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Re: How to measure the guitar's scale length

Post by JohnB » Fri Jan 27, 2017 2:07 pm

Google is your friend.
Hermanos Conde 1968, Stephen Frith 2007 "Guijoso", Christopher Dean 2018, Ana Maria Espinosa 2014

drmlyung
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Re: How to measure the guitar's scale length

Post by drmlyung » Fri Jan 27, 2017 6:15 pm

Beowulf wrote:My 1971 Yamaha GC-10 measures 662mm from the front edge of the nut to the middle of the saddle for both the 1st and the 6th strings. The saddle is not compensated except for the 3rd string which is cut back at the saddle ~ 1mm. Thus the scale is exactly 662mm for the 3rd string as the saddle compensation is right to the centre of the saddle. This suggests that the actual scale for the other strings is ~ 661mm as those strings leave the saddle at the front edge. The actual "playing" length may be slightly greater as the string is not locked at the nut and saddle and will vibrate behind the leading edges, particularly when played hard. In addition, lower action and longer scale guitars require less compensation as the strings do not stretch as much when fretted.
Thank you for your kind comment. Your measurement is in agreement with the Yamaha factory's published archive data.

It seems in close agreement with my measurement, considering that there are always minor measurement errors.

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Beowulf
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Re: How to measure the guitar's scale length

Post by Beowulf » Fri Jan 27, 2017 8:33 pm

drmlyung wrote: Thank you for your kind comment. Your measurement is in agreement with the Yamaha factory's published archive data.

It seems in close agreement with my measurement, considering that there are always minor measurement errors.
You are welcome...hopefully my playing errors are also "minor" and not "major". :D
1971 Yamaha GC-10 (Hideyuki Ezaki)
2017 Yamaha GC82S (Akio Naniki/Naohiro Kawashima)

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petermc61
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Re: How to measure the guitar's scale length

Post by petermc61 » Fri Jan 27, 2017 10:07 pm

I always measure scale length ONLY between frets to eliminate compensation of both the nut (typically 0.5mm) and saddle (typically 2mm). Also, I always measure between the tangs in the fretboard (since they are far narrower and eliminate guessing the top of the fret) or the back of frets. Then, I use a simple calculator derived from the optimal spacing of a 650mm guitar to determine the scale length. If you measure between the first fret and the 12th fret multiply what you measure by 2.25. If you measure between the first and 15th fret then the multiplier is 1.91. Do it both ways and average your results if you want.

Of course, you could measure all the fret positions and then do a least squares error optimisation in Excel of similar and get a better answer, but that's probably being a bit silly unless you are in the business of optimally designing compensation for guitars or similar.

Peter

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SeanWinkler
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Re: How to measure the guitar's scale length

Post by SeanWinkler » Fri Jan 27, 2017 11:39 pm

Peter's post implies what to me is the most important thing to remember about scale length: it's about fret placement, not string length. So measuring things other than fret spacing doesn't really make a whole lot of sense.
Remember Anthony Weller, please help. Contact myself or Aaron Green for details.

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Beowulf
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Re: How to measure the guitar's scale length

Post by Beowulf » Sat Jan 28, 2017 3:09 am

Okay...I measured between the tangs of the 1st and 12th frets. Result: 294mm. Multiplied by 2.25 = 661.5mm scale length. This is between the 662mm (3rd string) and 661mm for the other strings...so we have a pretty close agreement. Again though, the actual playing length may vary.
1971 Yamaha GC-10 (Hideyuki Ezaki)
2017 Yamaha GC82S (Akio Naniki/Naohiro Kawashima)

Pat Dodson
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Re: How to measure the guitar's scale length

Post by Pat Dodson » Sat Jan 28, 2017 10:54 am

Any of you guys fancy an adventure? :)

https://qz.com/894503/india-is-going-to ... arthquake/

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Beowulf
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Re: How to measure the guitar's scale length

Post by Beowulf » Sat Jan 28, 2017 2:25 pm

Pat Dodson wrote:Any of you guys fancy an adventure? :)

https://qz.com/894503/india-is-going-to ... arthquake/
Ho, ho, ho...I hope for their sake that it is more than a few millimeters. Otherwise the measurement accuracy will be swamped by the margin of error. :mrgreen:
1971 Yamaha GC-10 (Hideyuki Ezaki)
2017 Yamaha GC82S (Akio Naniki/Naohiro Kawashima)

drmlyung
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Re: How to measure the guitar's scale length

Post by drmlyung » Sat Jan 28, 2017 7:18 pm

Beowulf wrote:
Pat Dodson wrote:Any of you guys fancy an adventure? :)

https://qz.com/894503/india-is-going-to ... arthquake/
Ho, ho, ho...I hope for their sake that it is more than a few millimeters. Otherwise the measurement accuracy will be swamped by the margin of error. :mrgreen:
Could be with some "major" errors. :lol:

Joe de V

Re: How to measure the guitar's scale length

Post by Joe de V » Wed Feb 08, 2017 5:14 pm

Whatever measurement system you use remember that the spread of your fingers "shrinks" slightly when you are playing the fret-board.
Your fretting hand fingers do need to bend to play the correct fret/string location. The reach from pinky to index finger will then be a bit shorter than when you measure your finger spread on a flat surface. In my own test-case I am one fret shorter when playing than when measuring without playing.To play well you need to be comfortable without exposure to "finger fatigue".

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