Replacing the F-601L stiffener^2h

Today I made a replacement F-601L firewall stiffener.

First, I needed to remove the old stiffener. The most straightforward way I could think of was to lift it up after removing both of the F-695 gussets and drilling all the rivets that are holding the stiffener to other parts.

The first couple of rivets are drilled.

One of the gussets is removed.

The whole stiffener is removed. Drilling all the rivets wasn't particularly difficult, the same procedure as always: drill the head with a smaller #40 drill bit, then "tear it off" with a #30 drill bit, pull the rivet. None of the holes were damaged (except for maybe a slight stretching due to the riveting).

After inspecting the stiffener, I found that I had actually damaged a few other holes, too! I don't know if I was too tired that day or what, but apparently when drilling blind, I need to make sure the drill bit actually hits an existing hole. Good thing I decided to replace the whole stiffener.

Then, I cut a new piece of angle. I noticed that the stiffener is completely symmetric, so I just match-drilled the firewall holes using the old stiffener (instead of drilling them through the firewall—which is already dimpled!).

Everything fit perfectly fine. Luckily, it seems like this part wasn't too difficult to fabricate and replace.