[DaninVan]

Dave; the original would have been done on a shaper, most likely with custom ground knives. When I needed mouldings to match existing, 'BC Sash and Door' would take my sample, grind the knives, and charge me if I recall correctly $75Cdn. for the process, plus a basic charge for the first X number of ft. of moulding, then a fee of Y for each additional ft. of machined moulding.
I didn't get to keep the knives either.
But you know, it got the job done and the clients were happy.

 

[DaninVan]

Just to clarify, Dave; are you saying the curved portion is a true arc, or is it a segment of a parabola? A true arc would have a constant radius. The shoulders at either end aren't relevant to the radius.