Sometimes I wonder what life was like before I started deburring, dimpling and countersinking the forward fuselage... The more pieces I finish, the more small tasks show up.

Today's part is the firewall. I deburred the holes in the steel before but somehow still felt a lot of sharpness around the edges. I sanded them lightly and deburred again making them feel much smoother.

At the same time, I also deburred and smoothened all the holes on the engine mount brackets. These will hold the hole firewall forward weight so they are very critical.

Once that was done, I dimpled all the steel side #40 holes. I am using the Skybolt locks later on to hold the cowling so I will not have hinges but small attach plates that get rivetted to the side of the actual firewall flanges. These plates will get countersunk.

After dimpling, I realized there is a second row of rivets on the bottom skin so also needed to countersink the F-601M1 stiffener (angle) on the bottom of the firewall.

Here is the completed firewall, can't think of anything else at this point so I believe this will go aside until final assembly.

As I had some questions on the edge distances of my tank attach brackets and F-713 longerons, I held back dimpling this row on the side skin.
In the meanwhile I got green light from Vans to 'build on' and so dimpled the remaining holes line.

Next I also enlarged the pilot hole on the forward side near the tank bracket to the 7/16" dia hole. Used the step drill for that.

This will take an AN833-4D elbow fitting later on to pass the vent line through the side skin. (see DWG36).

I also wanted to make the second hole for the fuel line pass through. This takes a rubber grommet of 1" diameter (AN931-6-16) but then found out that I have no such cutting device.

My largest rotacut is 7/8" and the first biggest hole drill is 1" 1/8". So both are no good. I will probably use the 7/8" and enlarge the hole with a used 1" deburr wheel in the die grinder.

Next task was to deburr the last 2 rows on the center fuselage bottom skin. I first edge formed the end as this is the bottom most skin that hangs over the tailcone skin. (only aft most line).
Also deburred the aft baggage rib flanges and the F704's
Next dimpeled the holes in the aft bottom skin.

My center fuselage looks pretty much stripped down naked again pretty much to how it started a long time ago.