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Using used guitar necks, getting correct scale?

I get used necks from my local guitar shop for misc CBG/instrument projects. I can figure out the scale on most because I can simply measure them from the original guitar/bass etc. However, I just got a nice neck that I want to use on CBG, is there a way to figure out the correct scale on a fretted neck using only the neck and existising fret board as a reference. It is a 22 fret 4 string neck (uke?), unfortunately there are no manufacturing markings to try and research from.

Thanks

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Permalink Reply by Thomas "Duck" Petry on July 21, 2012 at 5:24am

In the standard fretting isn't the 12th fret half of the scale length? Should be an easy calculation.

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Permalink Reply by Jim Woods on July 21, 2012 at 6:07am

nut to 12th fret x 2 = scale (saddle placement)

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Permalink Reply by Tom on July 21, 2012 at 9:17am

Ok, so I am slow, but I am seeing something to be learnt here as well.

I just always put my saddle/bridge where I wanted it ,ie, whether 24 1/2, 25 - 25 1/2 or whatever and assumed that was what my scale lenght was.

For fret placement I just used once, whatever I had at the time as a template, and have always used that to mark my fret placement on all other builds.

Now I admit I have only made 3 so I have much to learn and improve on.

SO, can anyone here not only explain the 12 fret is half and times 2 is the saddle/bridge placement of the scale lenght, but the why's and what happens if thats not followed and any other info that to those that already in the know, seems pretty simple stuff.

And I will give thanks in advance cuz I know there are a lot of SHARP/knowledgeable guys out there, and have been always willing to share and help out !

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Permalink Reply by The Phrygian Kid on July 21, 2012 at 9:47am

Because we work in a twelve tone system, after twelve frets the distance must be exactly half in order to double the frequency and play the same note as open an octave higher. Hope that helps. Ps its called the rule of 18 but the actual ratio is more like 17.817.. It's te twelfth root of the distance from the last fret above

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Permalink Reply by Jim Woods on July 21, 2012 at 10:27am

Tom,

If you are making a new neck, you can fret it to whatever scale you have determined with your bridge placement. in that case the 12th fret will be 1/2 the total scale.

The poster was asking how to determine the scale of an existing fretted neck, in whch case the bridge will be 2x the distance from the nut to the 12th fret.

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Permalink Reply by BUGGY (C) on July 21, 2012 at 9:22am

Is this not just the rule of 18ths?

Each fret position is an ever decreasing 18th of the overall distance left between the nut and the bridge

I have an excel spread sheet somewhere for this.

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Permalink Reply by BUGGY (C) on July 21, 2012 at 9:24am

http://www.musemath.com/miscellany/ruleOf18.html

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Permalink Reply by BUGGY (C) on July 21, 2012 at 9:26am

http://homepage.ntlworld.com/coleman005/Fretting%20Calculations.htm

Hope this helps

But ascale rule sure helps... I want one!!

BUG

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Permalink Reply by Suspect Device on July 21, 2012 at 10:50am

Hey Bug, you can make your own out of aluminum yardsticks for about 3 bucks a pop.

Attachments:

fretscaletempls1.jpg, 121 KB

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Permalink Reply by Tom on July 21, 2012 at 10:55am

Now thats SWEET !!! Good idea :)

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Permalink Reply by The Phrygian Kid on July 21, 2012 at 11:15am

First time I measure out a new scale length I slot it into a pine 2x1... Or one of the sides of an existing one..
On this template I'll slot a rediculous number of frets, around 30 or so, and I'll pop a slot in at the bridge location as well. Sometimes I'll use it for a shorter scale by treating the third or fourth fret or whatever as te starting point or nut..
Then I use that for a template. My 600mm one has done over 50 necks now