Took off three days to recover from surgery. Completed riveting the COM antenna doubler with Ellicia. Used LP4-3s to tie the old doubler to the new doubler. Completed assembly of the crotch strap brackets and installed the brackets. Installed the 6 nutplates on the center section that were removed for landing gear mount fitting. Opened up the clearance holes in the firewall nutplates as needed so the bolts would fit without rubbing.