Arc

A jig is built to router out the arc on the bottom front component and the top front rail

 All components are riped to size and then crosscut 2" longer than needed. they must all be the same size for the jig to work. The jig must hold the component firmly without play.

This Plywood arm is prepped to receive the plunge router.

The router base is screwed onto the plywood.
Usually there is a plastic plate attached to the base with 3 screws. They were removed and used to screw the plywood to the base.

A hole is cut in the middle where the cutter is located. It is a good Idea to cut a big enough hole with a forstner bit be able to see.

The radius of the arc is found perpendicular to a tangent line. This is where the plywood is pinned.

Components can be bandsawed slightly larger than the arc to relieve stress on the router bit.

The machine marks from the router are scraped off before abrasives are used. 

Surface Prep before assembly