For my first CBG, I wanted to test my limits and see how far I could go with building a guitar. None of these "fret-less three-stringers" for me; no, I wanted a fret board and at least four strings, which I felt was the limit before I'd have to worry about bowing the neck. So, wanting to be sure I was understanding all I needed to do, I ordered David Sutton's book "Cigar Box Guitars", and waited patiently for it to arrive.
When it finally came in the mail, I read through it carefully, and began my first build. The book did not tell how to figure out a fret scale pattern; the best it would do was tell me to go "fret-less", or advise me to copy over from an existing guitar of the scale length desired, or order fret templates on line.
So I built my first guitar, and decided it was not going to be my last ... anybody hearing me out there? (Laugh!) But, because my first box was on the small side, and I wanted the neck to look aesthetically pleasing and well matched, not long and gangly, I chose a 21.5" scale, which, luckily, I had a guitar in my collection of that length!
I then realized that what I needed was an efficient fret scale template, and I began to search for a free one online that I could download. No such luck!
I found plenty of sites that gave the scales in millimetres. Millimetres? Really? Who uses mms in this country? And whose gonna count out 675 mms? Or how about this ... when they did give you inches, it was in the form of fractions, such as 1.758! Good luck finding that on a ruler!
But I did finally find a way to do it that was simple, elegant and fairly foolproof. It's called "The Rule of 18", and here's how it works.
First, you decide your scale length, and for the sake of the math coming out even, let's use 22.5". All you do is divide 18 into whatever your scale length will be; in this case 22.5 divided by 18 equals 1.25". That's an inch and a quarter, just to make it easy!
You get a sheet of large paper, and, using a straight edge, draw a line and mark off 22.5 inches. That's the horizontal leg of a triangle you are about to create. The vertical leg will be 1.25". Next, you draw the long leg of the triangle at the top, sloping down from 1.25" to the end of the 22.5" mark.
Now you take a compass, and set it at 1.25" and draw a quarter circle down from the 1.25 vertical axis to the horizontal axis. Take a protractor, and draw a straight line at the 90 degree angle at the intersection of the horizontal line. Draw it straight through the upper and lower sides of your triangle. This is your first fret mark!
You now repeat this process, using your compass to measure and mark the height of this fret from the top line, drawing out your circle again and marking the position of the second fret.
You will repeat this process for as many frets as you wish to use on your fret-board. When you have finished, mark out the width of your fret-board below, and cut out your paper fret-board scale.
Viola! You have created your own fret scale pattern, which you can use over and over and at no cost. And the best part is that this will work for any scale length you chose, thus taking the mystery and the clumsy "borrowing" from another guitar out of the process!
I am indebted to David Beede for this tip, and you can find out more information and see illustrations of this procedure at http://www.davidbeede.com/FretCalcGraphic18rule.htm.
I know it works, because I just completed a 22.5" build using this method. So, happy building!
See you next time! The Music Man Tim :))