First task for today was to drill out the 10 rivets which I squeezed yesterday attaching the rear spar doubler bars to the rear spar bar. 20 minutes later, I had 'em all out.

After removing the 10 rivets, I installed the ones which were trapped under the rear spar doubler bars only to drill them out a few minutes later. The vertical members of the F-705 bulkhead get riveted here as well. Sigh.

My order from Aircraft Spruce came. I purchased some AN426AD5-22 rivets and some AN509-8R20 screws as two possible options for attaching the bars to the carry through spar.

I made a little drilling block out of a piece of oak to help me keep the drill bit straight while drilling these holes up to #20.

After adjusting my #8 countersink way up so that I could use it to countersink for the 5/32 rivets, I made several passes at countersinking this hole. The first few times I didn't get any chips, so I kept adjusting the depth downward until one time it really dug in and went way too deep. Arghhhh! I must've had a burr in the hole or something that was keeping it from cutting. Having this countersink so deep is never going to work. Looks like I'll be using screws to hold these puppies on after all.

The good news is the countersink was pretty much the perfect depth for the screw head.

I suspected this may have been the case when I was ordering these screws from Aircraft Spruce. They're slightly too long. What I really needed was AN509-8R19 screws instead of -8R20, but Spruce didn't have any of that length. I'll check around tomorrow and find someone who carries -8R19 screws.

After that, I installed nutplates on all the baggage floor ribs.

Last task for the night was to cleco the baggage floor ribs and the F-704 bulkhead in position.