Time to put things back together again! Before the main spar goes onto the jig, all of the ribs (minus the outboard rib) need to be riveted on. I did remember a few gotchas from the last wing, so was able to change the order of a few steps here to save me some time down the road. For example, the rib flange tabs that slide under the spar are supposed to get final drilled later on with the skin and spar. I learned last time that that's kind of pointless though. The rib tabs are super flexible, so move all over the place and inevitably get drilled oblong if done with everything else. Instead, I just final drilled those tab holes to size on their own and did the same for the matching spar holes. That way the tab can simply be moved into place when it's time to rivet, which given the flexibility should be fine. Normally you drill things to final size while assembled so you can take out minor variations in layout (even 1/1000" offset each direction between holes in different material can make getting a rivet in a pain), but there are some pieces where that's just not worth it. I think this is one of them.
