The ‘linings’ or ‘kerfed linings’ are glued to the edges of the bent sides. They provide a bigger gluing area to attach the top and back, and allow you to cut into the side to add bindings and purfling without cutting off the top or back. Many small saw cuts (kerfs) with only a thin strip of connecting wood allow the strip to be flexible.
I make my own linings because: 1) it is hard to find a smaller size used in ukuleles, most are made for guitars. 2) I use what are called ‘reverse kerfed linings’, where the saw cuts, the kerfs, are placed towards the side, and the solid connecting strip is to the inside of the instrument. These are much harder to find commercially than regular linings. 3) I like the cleaner look of the linings, with that solid strip towards the inside of the instrument. 4) I make linings from a variety of woods, and can match the color of the lining to the color of the side. So sides of caramel colored sycamore get mahogany linings, while sides of black walnut get black walnut linings. 5) (this is the most important) reverse kerfed linings make the side much much stiffer than standard linings. The whole instrument becomes solid once the reverse kerfed linings are added.
I glue the linings on with reinforced cloths pins to get a stronger clamping pressure. For the reinforcement I have tried rubber bands (a bit bulky), sections of inner-tube glued together (messy to make), and lately doughnuts cut from surgical tubing.
