See the entry from 12/28/2008 for part 1 of the door frame construction.
After the arch is cut and faired, the groove for the panel and the sticking need to be applied to the rail. Having the groove and sticking already done on the shoulders provides a reference for adding them to the arch. I set a mortise gauge to the proper groove width and offset by referencing off of the shoulder portion. I then scribed for the groove all around the inside of the arch. I made the scribes as deep as I could to provide a good reference for my chisel. I then used a 1/4″ chisel bevel down and pared away the waste between the scribe marks. I needed to pare in from both sides towards the center for obvious reasons. Once the sides of the groove were established, they helped to guide the chisel as I deepened the groove to it’s final depth with continued paring.
I suppose I could have made a custom scratch stock type tool or something similar to a cooper’s croze to cut the groove, but it’s really not necessary. The groove is basically a long mortise so a chisel works fast and easy.
The fillet of the sticking is laid out next. I simply used a pencil and used my finger as a fence to draw the line a consistent distance from the edge as shown in the picture above. A marking gauge with a curved fence would work as well but again is not really necessary in this case. I am only marking a decorative element, not a joint surface so super precision isn’t needed.
To define the vertical surface of the fillet, I outlined the fillet with a 1/2″ #4 gouge. The curve of this gouge was a good match for the curve of the arch. I made stab cuts all around the curve to the depth of the fillet, keeping a portion of the gouge in the previous cut as I worked around to keep the curve continuous. Great care must be taken at the top of the curve to make sure not to split a piece off since the top of the arch is long grain.
With the vertical part of the fillet outlined with the gouge, it is simple work to pare away the waste to define a rabbet all the way around the arch. I again used a chisel bevel down for this task and pared down until the height of the fillet looked right and matched the height at the shoulders.
I then used the chisel, bevel down again, to round over the rabbet to match the sticking on the shoulders. This carving needs to be done from both sides toward the top of the arch, working with the grain to avoid tearing out a chunk. Care must also be taken at the top of the arch to avoid lifting a splinter while carving. Make sure to take it slow and come in from the other direction if fibers start to lift.
After carving, a little sanding with 220 grit sandpaper finishes off the sticking. Next it’s on to the raised panel.