So, I am working on my 3rd bass now, to be named Jennine. One of the features she will have is a scroll, pretty much like the headstock scroll of a cello or double bass, except this scroll will not be on the headstock. Where it will be shall be revealed later hehe. This brings me to the point of this post: Making scrolls. I have never made one before, so I thought this might be a good place to post the learning process for the benefit of anyone else out there who has been thinking about it.

I did a bunch of research on the math of a good looking scroll, and found some fun stuff out. First, the name of the scroll is a Volute or Acanthus scroll. These are found in nature, such as the Nautilus shell. The next things I found out, are the actual ratios involved in duplicating the Volute scroll. There are 2 primary ratios used, each producing a slightly different final form. The ratios are 7:6:5 and 6.5:5.5:4.5. There are other ratios used, but these tend to be the most common with 7:6:5 used mostly on instrument headstocks. For my scroll I am using 6.5:5.5:4.5.

Now for how to apply these ratios. If you are making a 6" scroll, measured from the base to the top, you begin by drawing a vertical line 6" long. Call it AB. Then draw a horizontal line, call it BC. Another vertical line, CD, and so on. There is a little bit of Algebra involved now. I am not including the entire formulae here, but if you ask me to I will. Suffice it to say that if you use the ratio of 6.5:5.5:4.5, divide the first line length by 1.18181818 to get the next line length. Divide that length by the same 1.18181818 to get the 3rd line length, and so on. After you have drawn 4 sides, stop. If you prefer the ratio of 7:6:5, divide each side by 1.166666 to get the length of the next side. Now draw a 45 degree line out from each corner where the sides meet. You will see a rectangle in the center of the drawing. Find the center of each side of the rectangle, then draw a line to each of the corresponding scroll sides. I have labeled the center points 1, 2, 3 and 4. 1 corresponds to AB. 2 with BC, and so on. You will get something like this:


Please note that the top horizontal line is only there as a starting distance for the first arc. Also note that I have labeled the sides AB, BC, CD, and DE. Look at the pic below. Draw arcs with the centers at: 1, arc from A1 to A1. 2, arc from A2 to A2. 3, arc from A3 to A3. 4, arc from A4 to A4. Your drawing should look like this:


Using this process you can continue drawing the arc inward as far as you wish. I end the scrolls with a circle in the middle. I made the scroll layout for Jennine starting with an 8" height, as seen in the pic below.


And finally, the finished scroll, which I have reversed and sized for making the template.:


The next posts in this series will cover the making of the template, then the routing of the (practise) wood, then finally the actual carving and shaping of the final (practise) scroll. Let me know if you hate this post, or have an easier way to do it.