Scooping for comfort
To shape the arc on the top edge of the centers (A) use a scooping jig [Drawing 3].
1 To shape the edge of the 1⁄2" Baltic-birch base, start by using a fairing stick to lay out the curve on a center (A) [Drawing 1, Photo I]. Cut the curve at the bandsaw and sand it smooth. Transfer the curve to one edge of the jig base along with the hole locations. Bandsaw and sand the curve smooth, drill the holes in the base, and glue in a pair of dowels. Add the supports and locking tabs. 2 Remove the bulk of the waste on each center (A) at the bandsaw. Use the jig to rout the remaining waste [Photo J]. A segmented compression bit [Sources] helps to eliminate chip-out along the top and bottom edges of the centers.