Dot Marker Position Gauges

Copyright © 2002 R.M. Mottola

[This article originally appeared in American Lutherie #72. It has been updated.]

Post Publication Note - This article describes the use of the same dot marker position gauge that is described in the book Building the Steel String Acoustic Guitar. The example instruments in the book both have the same scale length, and a dot marker position gauge for that scale length is included in the construction templates for the example instruments. Here, gauges are available for download for a variety of common guitar and bass scale lengths. In the original article, the gauges were printed on the page for photocopying. Here, they are available for downloading and printing.

Every time I'm marking out the positions of the dot markers on a fingerboard I promise myself that next instrument I'll take the time and make a nice drilling template just for this purpose. The reason I never actually fulfill that promise is the next instrument will not be the same as the current one. If I was in any kind of a production mode it would be easy to justify the time to make the template, but I am not. If you find yourself in the same boat then these little dot marker position gauges may be the next best thing. They work well and do save a lot of time. Without modifications, the gauges can be used to directly locate the centers of all single dots on the playing surface, as well as all single and double dots on the fingerboard edge. A small modification can be made to a gauge so it can be used to directly locate double dots on the playing surface as well. The gauges are CAD drawn and scaled for some common guitar and bass scale lengths. I've tested the 24.75", 25.5", and 34" gauges for accuracy.

Figure 1

To prepare the gauges, first download the gauges and print them onto card stock and cut them out. If you print the page onto clear acetate you can make gauges that you can see through, but the black lines don't show up too well on top of an ebony fingerboard. Take some care when cutting the right side and bottom end of the gauges, as these surfaces are reference surfaces. Since card stock is cheap you may want to print more than one copy in case one of your cuts doesn't come out just right.

Important Check: Be aware that a misaligned printer may make the copies bigger or smaller than the original, and this will cause problems. Each gauge should measure 1.5" x 2". If not, try a different printer.

To use a gauge, chose the one for the scale length of the instrument you are building and position it over the slotted and center-lined fingerboard, so that the bottom edge is positioned in the center of the slot for the 3rd fret. Make a mark across the centerline of the fretboard extending from the gauge line with the '3' above it, as shown in figure 1. That's the center point to drill the hole for the 3rd fret dot marker. Repeat the process for the rest of the dot marker positions. The unmodified gauges don't have any provision for locating the positions of the double dots relative to the centerline, as there are just too many different fingerboard widths and tapers to accommodate this on a single gauge. So on the double dot positions you can use the gauge to locate the right spot on the fingerboard and then measure from the centerline out to the dot centers.

Figure 2

The gauges are used in similar fashion to mark the centers of the side dots on the fingerboard edge. It can also be used to mark the double dots here. To do this for, say, the 12th fret side dots, use the gauge to make a mark as if you were going to place a single dot here. This marks a place halfway between the 11th and the 12th frets. Mark the center of the two side dots on either side of this halfway mark by positioning the bottom edge of the gauge at the halfway mark, and then making a mark next to the short, un-numbered gauge line, as shown in figure 2. Then flip the gauge so it's upside down and make a mark on the fingerboard for the other dot in the pair.

Figure 3

As mentioned, a gauge can be modified so it can be used to directly locate playing surface double dots for fingerboards of the same width and taper. To do this, measure or calculate the distance from the centerline to the center of a double dot at the 12th and if applicable, the 24th fret positions. Mark these distances on the long 12th and 24th fret gauge lines as measured from the right edge of the gauge. Draw a line from the bottom edge of the gauge through these points, and cut the gauge along this line and out to the left side. There is an example of such a gauge in the set, the one labeled "Fender Electrics." This one will locate the center points of the double dots in between the first and second, and fifth and sixth strings respectively. To use the modified gauge to mark the centers for the double dots, position the gauge at the 12th or 24th fret with the right edge on the centerline and make a mark next to the left hand 12th or 24th fret gauge line, as shown in figure 3. You just marked the center position for the left hand dot. To mark the center point of the right hand dot, slide the gauge to the right until the left end of the 12th or 24th fret gauge line is on the centerline of the fingerboard. Then place a mark next to the end of the right hand 12th or 24th fret gauge line.

Download

The downloadable copyrighted gauges are made available for non-commercial use only and may not be redistributed.

 Download Dot Marker Position Gauges (.pdf).