The function of the tools I use and how they work are explained here. Specific tools used are noted in bold.
The arch is made of three sections. Eact section is made of three layers. The board is resawn (sliced horizontally) on the bandsaw into three plies. This gives enough outer plies for the outside of the door. There wasn’t enough wood on the main board to make all the plies, so the inner plies are made of a different board, but because they’re internal, they wouldn’t be seen.
The arch segments are epoxied glued together, with the segments overlapping each other. This also results in an extended middle ply spline “tongue” that will be used as the connection to the side pieces (stiles). Once all the glue is spread and the pieces assembled, they are placed in the vacuum press. When the air is pumped from the press’ bag, atmospheric pressure clamps the plies together while the glue sets.
After the glue dries the arch is trimmed to its final dimensions using a pattern and a flush cut shaper head. The shaper head has a bearing that is flush with the cutters. The pattern is temporarily attached to the arch, and the bearing is run up against the pattern resulting in a perfect duplicate.