3 hrs on the closing brackets, etc.

Old bracket drilled out.  Other side also.

Overlaying the new bracket you can see it's mostly the top that needs to be ground down to get it to fit.

Trying to be very careful to not over-grind it this time.  I de-burred and primed the new brackets, so I'll complete this task tomorrow.

Put in M3 rivnuts in the center channel.