Drilled the F-732A channel to the F-732D angle on the top of the cabin frame. Drilled the F-732E angles to the F-732A channel and to the cabin frame.
Removed the channel and deburred all the loose parts.
Located the holes for the AN3-5A bolts that will attach the inboard sides of the cabin frame to the F-631D brackets. The plans call for these holes to be predrilled in the brackets, but I missed that detail. It was easy enough to locate them with the bracket still bolted to the frame, and definitely easier to drill them from the outside than the inside.
Deburred, rescuffed, cleaned and reprimed the F-631C/D brackets.