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Braces · Attaching the soundboard · Fingerboard · Finishing · Gallery of the completed oud
The two halves of the soundboard are jointed along one edge and joined with a joining fixture. It is simply two pins (screws) on each side of the halves, attached to a flat board. They are placed a bit narrower than the width of both halves, so they are raised slightly in the middle. To clamp the joint, simply push down at the joint and place a heavy object until the glue cures. I also placed a strip of newsprint under the seam to prevent the boards from adhering to the fixture. Waxed paper should work too but I have read that it inhibits the glue drying process.
The joined soundboard. A friend with a drum sander took it down to just under 3mm for me. The rest will be done by hand.
A close view of the grain. It is not the prettiest piece, but the tone it produced when tapped was the best of the samples I had, so I used it. The wood is Livane Spruce, from Turkey. I will add further opinions of the wood as the oud construction continues.
The center of the soundboard. After much research, I decided not to bookmatch the top, for various reasons. Oud luthiers use both bookmatching and slipmatching. Both apparently have their advantages. On that note, I decided to end the research after about four days and get on with the construction. The grain lines are nicely quartersawn and fairly tight. The stiffness of the top is fairly uniform across its width, despite the variable grain line spacing.
The left side (looking towards the neck)
The right side.
The rosette around the soundhole is made up of small tiles of walnut and maple. I glued up different thicknesses of walnut and maple as well as veneer in order to copy a pattern found on a 1908 Roufan Nahat oud. See below for an image of this pattern
The 1908 Nahat oud with the tile detail.
A closer view of the tile blanks.
The blanks sawn into 3mm thick slices. I left them thick for easier handling. This amount should yield enough for several rosettes.
I picked up this Zona razor saw and miter box at the local hobby shop for only $7.50. It cuts on the pull stroke, has 32 tpi, cuts extremely smoothly and leaves no tearout or fuzz of any sort. It works very well for cutting the individual tiles.
Here are some tiles laid out in order. These tile will also be used at the edge of the soundboard after it is glued to the back.
A quick mock-up of the rosette. The channel is a test cut in MDF with the laminate trimmer for proper diameter, which is 122mm on the inside of the rosette, which itself is 4mm wide. The tiles will have to be slightly sanded to the curve and angled a bit at the ends to fit properly. There will also be a line of walnut veneer on the inside and outside of the rosette to create a border.
Here I am sanding the end of one of the slices. This surface is the inner edge of the rosette. (The sanding wheel is this diameter) The jig is from Cumpiano and Natelson's book on guitar building, specifically, the section on inlaying an abalone rosette on a steel string guitar. My rosette is essentially the same, replacing the abalone sections for wood. I sand the end and cut off a tile, and repeat until I have about 20 tiles.
This is the second half of the jig which sands the outer radius of the tiles. It is just a little stick that holds the tile while it pivots at the correct point. This not only makes the outer curve on each piece, but also sands each tile to the same width. It is used for both the maple/walnut tiles and the veneer tiles.
The tiles after sanding both curves.
The larger tiles still need to have the ends tapered. The veneered tiles remain as they are, so as not to remove any of the detail.
The jig (shooting board) I made for tapering the curved tiles. The top block is a section of the inside diameter of the rosette. Since I only tapered the maple/walnut tiles, I cut the flat edge off center (narrower side) to compensate for this. If I were to taper all the tiles, I would have made the straight edge bisect the center point of the circle. The plane is a Lie-Nielsen Large Shoulder Plane. Lie-Nielsen makes the finest hand planes, and I am pleased to own two of them. The second one is the 164 Low Angle Smoothing Plane which I use quite extensively.
I hold the tile in place with my thumb while planing with the right hand.
The maple pieces at the ends are planed until the taper goes across the entire tile end.
A test fit in the sample groove. The taper is correct. The tiles butt neatly against each other.
I made a test cut in some scrap wood to set the router to cut the correct inside diameter. I left the screw holes in the clear sub-base a bit large to allow for minute adjustments. When I got the correct diameter, I went ahead and cut the first groove in the soundboard, which I am doing here. I am using a solid carbide, 1/8" (about 3mm) diameter spiral downcut bit. The spiral downcut shape of the bit keeps the edge very crisp and causes absolutely no fuzz or tearout, like a normal router bit might. I repeated these steps to cut the outside diameter. The channel is .127mm (.005") wider than the tiles plus two lines of veneer to allow for glue space. This is a very minute amount, and was measured very carefully with a dial caliper. Needless to say, the tiles and veneer are accurately made to a tolerance of about a thousandth of an inch. The depth of the groove is just over 1mm. Hankey's book says to make it 1.5mm, and then sand the back to 1.5mm thick. This means that the rosette is attached to the soundboard only on its edges! However, when the rose is attached later, this becomes reinforced by the edge of the rose being glued to the back of the soundboard. Nevertheless, I opted to leave the channel a bit shallow to keep the top intact. The top is fragile enough as it is.
Test fitting the tiles and veneer lines in the finished channel.
The finished rosette glued in the channel. I used PVA (white) glue for its longer open time. I began by covering the bottom of the channel with glue about 5cm at a time. Other than the first tile, I didn't bother gluing the contact surfaces of the tiles. As they are pressed in place, the excess glue is squeezed out and takes care of these joints. I laid in the first tile with the veneer and pressed down, laying in alternating tiles and spreading more glue as necessary. The veneer has a tendency to raise up, so I made sure I pressed it down at each tile insertion. I have yet to see whether I was judicious enough in this after I plane down the tiles to the surface of the soundboard and reveal any mistakes.
The rosette after planing it flush.
The completed rosette.