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How to calculate and implement a fanned fretboard?

Hi All.

I don't know if you have seen Bairfoot Cajun's fan fretted CBG (shown below and a video at this link), but it seems pretty cool and has gotten me interested in trying to build one in the near future. Before I do, I want to make sure I know how to go about building one.

For my initial research on the topic, I Googled "Fanned Frets" pulled up a lot of interesting links. Here are 3 that I thought were particularly interesting.

1.) Thread on Hand Made Music Club House.

2.) Thread on Mandolin Cafe

3.) Page on Novax Guitars website.

It seems like the rules are rather "loose" as to how you can make fanned frets, but you don't really want to angle them at too extreme of an angle as it will adversely affect playability. You also have to decide where the fret that will be at right angles to the side of the neck will be. Some do it at fret 0 (nut), others do it at fret 12, or fret 8 (like it looks on the Cajun's CBG). If I understand these threads right, all you need is to decide what scale length you want for string 1 (your treble string) and what scale length you want for your base string and then run both those scale lengths through a fret calculator and the plot the series of dots under each respective string, then take a straight edge and connect the 2 dots for each angled fret. Then cut the fret slots with a fret saw and install the frets as per normal procedure. Also, you may want to use one of the fret calculator that prints the fret scale out on paper (like wfret.com) and then align these two scales at fret 12 (or 8 or wherever you want your perpendicular fret to be). Does this sound right to you all? When I get back home to China, I think I might try one. They sound interesting. Any constructive or informative comments or clarifications would be appreciated. Thanks.

-Rand.

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Replies to This Discussion

Permalink Reply by Rand Moore on July 17, 2011 at 4:53am

Hi All,

The FretFind2D fret calculator lets you play around with lots of parameters and graphically displays the results. If you are interested in this topic and want to study the parameters, it is well worth playing with (and free, too). Each parameter is explained separately when you click on the [?] question mark associated with it. Here's an edited screen shot of FretFind2D set with parameters so it would display 4-strings with the perpendicular fret set to fret position 8. A couple of other parameters were also probably tweaked.

So, check it out.

-Rand.

Permalink Reply by BenBob on July 18, 2011 at 1:55pm

Sounds right to me. But are fanned frets easier to play? How so? Or do they just look cool? Limitiations on strings isn't an issue anymore, so I wonder what the purpose is now. The DO look cool!

Permalink Reply by Rand Moore on July 19, 2011 at 9:35am

Hi BenBob.

The idea is to improve the bass sound of the bass string(s) of your instruments by making them longer than your treble (and middle) strings. I imagine it works better on 6-, 8-, 10-, or 12- stringed instruments than a 3 or a 4 stringed instrument. In the video that Bairfoot Cajun made of his three stringer, it sounded really nice; making me reconsider it for smaller instruments. I haven't every played one, and so I can only go on hearsay. Unfortunately, that hearsay is such that some people say it's easier and some people say it is harder, and they are playing on different instruments and so, maybe they're comparing apples to oranges. So, for now it's something for us experimenters to play with and not a new hot feature that buyers of CBGs are hot to have. At least one luthier requires folks who want him to make one to come in and play one of his instruments a while before they decide. That may be a good idea as we all want to keep our customers happy.

-Rand.

Permalink Reply by BenBob on July 20, 2011 at 9:38am

I see. Let us know how it turns out!

Permalink Reply by Rand Moore on July 20, 2011 at 2:55pm

Hi BenBob,

Well, I wasn't planning to do a build quite this soon as I am vacationing in the States and my "shop" (and I use the term very loosely) is back in China. I did bring some of my most essential tools with me, so maybe I can build one. I'll just throw together a fairly no frills CBG and maybe do a diatonic fretboard (or neck). Maybe a 4-stringer. Let me think about it bit.

Anyways, here how the diatonic fanned fret fretboard layout might look like:

The number of frets I can put on will be 11 or 12 (14 counting frets 0 and 6.5). Treble string scale length: 21", Bass string scale length: 24". The perpendicular fret will be fret 7 (which corresponds to Chromatic fret 12). I might move the perpendicular fret to fret 6 so I'd have 5 frets above and 5 frets below. I'll have to think about this.

Also, this neck is a somewhat longer than I usually build and with the 4th string, it will definitely have more bass than I generally build.

-Rand.

Permalink Reply by Hayden A Butler on August 12, 2011 at 2:23am

I am new to the concept of fret "6.5" - what does it mean/do?

Permalink Reply by Rand Moore on August 13, 2011 at 8:21am

Hi Penfoot,

The 6.5 fret has to do with diatonically fretted instruments like the mountain dulcimer (MD) and the stick dulcimer. The MD was developed in the Appalachian mountains more than 150 years ago, a time when people were not formally educated in music. So, the folks who developed the instrument according to the musical traditions they had. As a result the original diatonic scale was a "Mixolydian mode" scale where the notes used and the fret layout on the fingerboard follow this pattern of whole (w) and half (h) steps: w-w-h-w-w-h-w. Now compare this note and fret layout pattern with the Major scales: w-w-h-w-w-w-h. The difference is that the sixth note is a half step flat in Mixolydian mode. So, sometime around in the 1940s, people started adding a "six and a half fret" to their mountain dulcimers to make it easier to play Major scale (Ionian mode) music. This "6.5" fret lies between fret 6 and fret 7 on the traditional MD scale and it provides a "proper" sixth note needed when playing a song written in a Major scale. Hence the name "6.5 fret". In some tabs and other articles this fret is also called " 6+ " and " 6* ", but all mean "six and a half fret". Since chromatic scale instruments like the guitar, bass, banjo, mandolin and ukulele already have all the "accidental" notes (frets), this was never a problem.