Materials Selection and Neck Block
Start by selecting the materials for the neck, top plate, bottom plate, bass bar, and ribs. The neck is normally a block of Maple. Cut it to 42 x 50+ x 250+ mm. Plane the faces perpendicular. Mark locator points with scroll template, then form a fair curve between those points to define the scroll. Punch peg guide holes with a centre punch. When done, the neck block should have fairly clear markings for future work in forming the scroll.
Top Plate and Bass Bar
Cut the top plate from an appropriate material, usually Engelman Spruce. If the top piece is wide enough, cut the Bass Bar from the edge. It should be 7 mm wide x the length of the piece. Plane the Bass Bar to about 6mm in thickness. Cut the remaining top piece to 108+ mm x length of piece. Tops are normally supplied as a block of wood cut almost all the way through the middle to create two symmetrical pieces. Separate the pieces and plane until the narrower side is about 6mm. The wider side will be 20+ mm.
Plane the wider edges as flat and straight as possible. Hold these edges together to check for fit. If any light can be seen along the seam, keep planing until there is no light visible anywhere along the joined edges. Finish the edges with a long straight sanding block.
Rub the edges together firmly, holding the pieces so that the profile is symmetrical. Apply glue lightly to both edges, clamp, and check for straightness.
Similarly cut the bottom plate from an appropriate material, normally Maple. The bottom can be one or two-piece. The choice depends on material availability and personal preference. For the remainder of this instrument, it shall be assumed that the back is one-piece. If using a two-piece back, join the edges in a similar manner to to top pieces.
If using a one-piece back, cut angles from the outer edges to form the ribs. These strips should be 3mm x the material length. This will leave the back piece with a similar profile to the top, with the edges about 6mm and the centreline 20+ mm.
Take the pieces cut from the bottom and plane one edge of each flat. Cut each piece 35mm wide. Sand to about 1 - 1.5mm in thickness using a thickness sander.