Setting the Neck (Shaping the Heel)

Before I can set the neck into the body, I need to prepare the heel for the dovetail joint. A violin-style neck joint differs from a guitar or mandolin dovetail because on a violin, the heel itself is the dovetail for the joint. This will become a little more apparent as the process progresses. First, I plane the heel to its desired angle (about 87 degrees from the fingerboard surface). Then I rescribe my centerline, and work with that to lay out the important dimensions here. The first of these is the width of the fingerboard at the end of the heel. I measure half that width and mark a line on either side of the centerline. Then I measure down 5.5 millimeters, which is my desired overstand. The overstand is the height of the fingerboard surface of the neck over the edge of the top. I mark that, then measure down my rib height (29 mm in this case), then I measure down the thickness of the button, which should be anywhere from four to five millimeters. I mark the desired width of the button (21mm) from this line and connect the lines to get my final (desired) heel cross-section.
And now for a brief interlude from our fingerboard. But boy, is that thing chunky! A violinist would have a hard time playing on a fingerboard the way it's sold. That's because what the suppliers sell are actually fingerboard blanks. Some players like their fingerboards shaped a little differently, depending on taste or possibly the peculiarities of the instrument, so suppliers can't offer a one-size-fits-all model.
This means I have work to do. No worries, though. The pre-shaping done to the wood simplifies the task quite a bit. And if you're wondering whether it's worth springing for the higher grade of ebony, I had to work through a tiny knot in my last fingerboard that implied it is. Now, I take this blank and plane the sides so that the width at the nut end is 24mm, the width at the other end is 42mm, and the edge of the fingerboard is not a straight line, but a smooth arc, dipping down a full millimeter at its deepest point. The cross-section of the fingerboard is rigorously achieved by holding a radiused template to the surface and checking for gaps.
The surface of the fingerboard is not straight along its length either, but dips in half a millimeter at the E string, and a full millimeter at the G string, again with a smooth (if subtle) arc along its length. Then I smooth and polish the ebony so it looks really pretty. Sometimes if I'm in the mood I'll rub a little lemon oil into my fingerboards. This makes them look nice for a while, but doesn't really appear to have a lasting effect. Can you see the difference in the two pictures? Probably not, but you'd definitely feel the difference on a fiddle!
So the next thing I do is spot-glue the fingerboard onto the neck. This will be important while I set the neck because I can use it as a reference for the centerline as well to determine the all-important neck angle. This just takes about three dabs of hide glue and and hour or so. Because I won't be stressing the joint, and because the joint is not meant to be permanent, I feel no qualms about working with the neck after so short an amount of time.
What I want to do with it now is shape the heel. These surfaces are going to have to be perfectly flat, and quite precise. But there's no reason not to go ahead and hog away some of the excess wood with my incannel gouge. This leaves some rough marks, so I don't want to go too close to my lines, but I like to get it pretty close anyways, because I'll save a lot of time doing things this way. I also like to flush up the neck to the edge of the fingerboard, as long as I've got my gouge out.
Of course, after the gouging comes the planing, and here's where I really need to be conscious of the heel's dimensions. It's very important when planing these dimensions that the centerline remains accurate. If you wind up with a 21 millimeter wide buttton, and your heel is perfectly flat and trued to the fingerboard, but you have 11mm on one side of the centerline, and the other 10mm on the other side, it's best to do some extra planing and go with a 20 millimeter wide button. Some might disagree, but I like to err on the side of saving work.
Notice when the heel's done that it tapers in width from the front to the back, but also from the top to the bottom. This is the same as the traditional dovetail shape you'd find on a guitar or mandolin, though quite a bit more solid. You'll also notice that the bottom of the heel still has plenty of excess wood (i.e. the thickness of the button, and then some). I leave this on so that I'll have room to adjust the angle and height of the bottom as I bring the neck to its final overstand and neck angle while setting it. But I've gone on for long enough, so that's a story for another blog...