Making the fingerboard holder
Prepare a precise block of hardwood measuring 270 x 60 x 30 mm, see Fig. 1. for its simple construction.
Make two strips of hardwood measuring 5 x 9 x 270 mm.
Get a fingerboard blank, put it on top of the block
Glue on each side of the blank the two strips.
Clamp down the strips.
Remove the blank.
Carve out the material between the strips according to the top radius of the fingerboard blank, see the bottom of Fig. 1. for the finished holder's wider end profile.
Shaping the fingerboard blank
Ebony is both very hard and prone to chipping.
Place the fingerboard blank into the holder and clamp the holder in the vice.
Plane the whole underside of the fingerboard down so that the sides are about 5 mm thick.
At the bottom, mark the w1 24 mm and w2 42 mm widths and create lines from these marks using your scribe. The lines may be made more visible by the application of white chalk.
Plane the sides down to the lines making sure that both sides stay at right angles to the bottom. If necessary readjust the height to 5.5 mm.
Remove the thickness on the underside of the fingerboard, starting at the 139th mm, gradually removing material of up to 0.5 mm at the very end of the fingerboard, see the dashed line in Fig. 2 This way, because the top of the fingerboard will later be planed a little concave towards the middle as well, the final thickness of the sides of 4.5 mm can be retained.
You may now, using a block plane, create a small concavity along the length of each side of max. 1 mm at the center of the fingerboard. Check with steel ruler.
Mark the hollow area ha, starting d 142 mm /6 mm from the neck root/ from the top end of the fingerboard, allowing t 3 mm for the sides. Use your compass at point x to create the arch, trace with a needle. Highlight with chalk.
Remove some material with a gouge, getting down to about 5.5 mm thickness, from point x up to the end. The final thicknessing is done with the fingerboard glued on the neck.
Mark a height line h of 4.5 mm on both sides of the fingerboard. That will be the final height of the fingerboard sides. Highlight with chalk.
Last, check whether the new underside of the fingerboard sits perfectly on the top of the neck. Sometimes the neck may twist a little as it dries and that must be corrected /plane/.
Trimming the fingerboard's ends
If you started with a premade fingerboard blank, which was already cut to the correct length of 270 mm and those cuts are clean, you can skip this chapter altogether.
Inspect the ends and decide which end to cut, if just one or both. Mark the correct length I of 270 mm.
Cut with your fine-toothed saw. Be extremely careful to prevent chipping.
Finish with sandpaper on a block of wood and/or a file. Make sure the new ends are at right angles to the underside.
