I spent an hour or so tonight prepping the firewall hinge on the upper cowl. Because of the tight curvature of the cowl in this area, the hinge eyelets bind together. This wasn’t a problem when fitting the hinge initially, but it has to be corrected before the hinge is riveted to the cowl. I filed bevels in each eyelet in the region of the hinge with the tight curvature.
Here you can see that the bevels provide clearance between the eyelets. I only did this to the forward half of the hinge, and only in the last foot or so on each end.
