As the subject came up in another build thread, I'm gonna explain how I laid out the multiscale fingerboard.
I didn't have time to prepare sketches, but hopefully it'll be clear enough!
First step:
Choose your scale lengths.
Dingwall goes for 37" and 34", I went for 920mm and 860mm, because I can use available Extra Long Scale strings (also I'm French, so I favored the metric system
).
Second step:
Choose your "pivot" fret.
That the fret that will be perpendicular (or closest to perpendicular ) to the fingerboard centerline. I chose the seventh because it give the same offset at the nut and twenty-fourth frets (in my case 20mm)
Third step:
Fingerboard length.
Mark out both ends (nut and 24th fret) of the longest scale length on the fingerboard's centerline. Mark the seventh fret. Then using the seventh fret as reference mark both end of the shortest scale length.
Fourth step:
Fingerboard width.
Using a square and the short scale length as reference, mark the width of the fingerboard at both ends (nut and 24th fret).
I don't remember right now what width I went for but as it is a matter of preference you should work it out depending on your bridge and nut spacing.
Draw a line connecting each mark on the bass side and do the same on the treble side. Using your square extent the seventh fret mark until it crosses both sidelines.
Fifth step:
Outer strings centerlines.
The sidelines represent the edges of the fingerboard. You need to lay out the scale lengths where the outer strings will be to unsure correct intonation. In order to do that just draw a line parallel to the sideline on each side. The offset is your choice, just use what you know is comfortable to your hands. I seem to recall I used 4mm (to the string center) on the bass side and 3mm on the treble side.
Sixth step:
Scale lengths.
Using the seventh fret as reference mark the nut ends of both scales. Then lay out both scale lengths along the outer strings centerlines and mark each fret position.
Seventh step:
Fretlines.
Now you only have to connect your dots to draw your fretlines. You should be very cautious because when you are close to the ends the angles can make it a bit fiddly.
You're done!
Then you can do whatever you wanna do, cut them lines and fret'em or go the fretless route...
In all of this accuracy is the most important aspect. I'm actually using a utility knife to scribe all the lines, as it makes a much finer line. Just be gentle and it will all sand out in the end. For scale length I use the
Stewart-MacDonald Fret Calculator.
There it is, I hope this helps anyone who considers the multiscale jump.
