Chapter 10
Fitting the Neck
to the Soundbox
After sanding the top of the soundbox, I stood it on end on one of my pieces of Maple scrap. Drawing around the inside edges gives me the basic shape of the top block of the soundbox. This is the piece that the tenon of the neck will fit into. I'll have to cut a mortise into this piece to accept the tenon of the neck, and because of the length of the tenon, it will extend through the thickness of this piece. For added strength, I decided to double the thickness of the top block. After sawing this piece out on the band saw, I used it as a pattern to lay out another piece just slightly larger, and then glued the two together. I also rotated the grain 90 degrees on the second piece.
Using a straightedge and my bevel gage, I determine the angles that I need to sand on the sides and back of the top block, and transfer those angles to the disc sander table. This operation requires going back and forth, sanding a little here, and a little there, until the top block fits snugly in it's location at the top of the box. This has to be glued solidly in place, so I take the time to make sure I get a good fit on all 5 sides. Once I'm satisfied with the fit, I also sand the front of the block to make sure that it clears the grooves in the sides that will accept the soundboard.
I used the same procedures to fit the base of the soundbox. The base and the top block are not parallel, so the angles on the back and 1/4 sides are not the same, but the angles on the sides are. Here again, it meant going back and forth, sanding a little here and there, until I got a good fit. Once the base is secured in place in the soundbox, I'll sand the bottom ends of the sides and back until they are flush with the bottom of the base.
Here you see the top block, ready to be glued in place. After fitting it to the soundbox, I laid out a centerline, and then drilled and chiseled out the mortise to fit the tenon on the neck. Unlike the joint between the neck and pillar, this joint needs to be a good close fit, so I carefully pared away at the sides of the mortise until the tenon just fit into place snugly. The mortise is also slightly deeper than the length of the tenon, but it does not go all the way through the top block assembly.
Here you see the relationship between the neck and the top block, as seen from the players point of view. The left face of the neck is on the centerline of the harp body. This is so that the strings will be nearly straight up and down. Many harpmakers are quite satisfied with this arrangement, and will just call this good enough. But I don't care for the way this looks, so I do something a little different here. I am going to widen this end of the neck, for a smoother transition between the neck and the body.
Now doesn't this arrangement look more balanced? I just cut two pieces that will glue to the neck and then be shaped down to create smooth flowing lines in this transition area between the neck and the body of the harp.
Another shot of the same assembly. You can see here how these neck doublers stop before reaching into the string area. Once they are glued in place, I have to make a rather tricky cut on the band saw to remove the excess. I turned the neck upside down on the band saw table, and started the cut with the blade next to, and parallel to the face of the neck. I rotated the neck both vertically and horizontally through the cut, so the blade exited on this side of the doublers, nearly parallel to the top of the soundbox. A large diameter sanding drum in the drill press then smoothed out this cut rather nicely.
Having all of that done, I could go ahead and glue the top block in place in the soundbox. While that was set aside to dry, it seemed like a good time to go back to the soundboard. After trimming the sides of the soundboard for a good snug fit in the soundbox, I re-established the center line. and marked the locations for the string holes. The easiest way to do this was to carefully fold the full size plan along the line that represents the face of the soundboard, and then position this fold along the centerline of the soundboard.
Now it is very easy to accurately transfer the locations of the holes where the strings must penetrate the soundboard. Just make sure that the plan is positioned properly along the length of the soundboard.
The next step was to fashion and glue on the internal string rib. This is a piece of Maple about 1/2" thick that glues to the INSIDE of the soundboard. It provides extra strength to absorb the stresses of all of those strings when they are tightened. This rib extends about 1/2" below the bottom hole location, and about 1/2" above the top hole location. It is also tapered from top to bottom. The bottom is 1 & 1/4" wide, and the top is 1/2" wide. It is sanded smooth, and then glued securely to the inside face of the soundboard.
For the first time I can fit up the 3 major components of the harp, and see how she's looking. And she looks good!
The base is still not added, there's more work to do there yet. For one thing, we still have to cut the mortise and tenon joint where the bottom of the pillar will lock into the base.
In this photo you can see how I shaped the widened end of the neck to get nice, flowing lines in the transition area. Now I need to finish the base, and then get down to some very serious sanding, sanding, and more sanding.
We're getting close now, and it's starting to look like a harp. In the next chapter we'll get it all together, sanded, and start decorating it with some nice Celtic designs, so check back soon!
Move on to Chapter 11
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