There are two openings in the framework for lighting, and in these areas the frame members in a few locations do not lap, but terminate in a 'T'. To fix the connections together, I will use a long screw. Since screws have unreliable purchase in end grain, I mortised the receiving frame member so as to fit a blind cross-grain pin.
Here, the pin has been driven in and is being trimmed flush:
I chose mahogany for the pin as it is a slight bit denser than the Yellow Cedar.
The screw should draw the connection up tightly:
I found a little space where I could put the perimeter frame up using the corner templates I took from the room, and position the other frame members atop so as to iron out the issues arising from a non-square room in the install location:
The joinery between the interior frame members is complete at this juncture. Here's a look at a mitered lap with mortise, with a regular mitered half-lap above:
The ceiling frame parts are nearly complete:
A view of some of the mitered housings:
The perimeter frame corners have a form of mitered and stub tenoned connection:
Those joints are a hair fat for the time being and don't fully close up at their 90˚ abutments. During the next fit up I will trim the miters so as to bring the corners tight together.
All for this round - thanks for tuning in. Post V come along next.