F-705 to side skin, countersink or dimple?

[bkthomps]

I'm having one of those days, I've looked over the plans many times but I figured i'd ask you guys

the sideskin to F-705 holes, did you guys countersink these or dimple them? the other question I had was the firewall to side skin section, the very first row of rivets is where the cowl hinge material will be mated, do I dimple the firewall with this row of rivets or do I only dimple the lower row in the stainless firewall flange

 

[704CH]

Dimple

I dimpled the sides of 705.. Looking forward during the build I match drilled the doubler to 705 before assembly and dimpled both at the same time. From there it went together well. You can use the trick Van's calls out on the Empennge spars, where you can take a quick turn of the deburing tool in the dimple to help the doubler lay flat in the chanel.

I dimpled both the firewall and the side skin.