Aileron bellcrank questions

Page 23-05 calls for the final drilling #40 and for 426 rivets to attach the nutplate to the right bellcrank but never calls out to countersink the holes. Before I remove metal I just want to be sure countersinking is correct.

Additionally are people using linseed oil in the bellcrank to reduce corrosion or can it just be left bare? I assume if it is primed it will wear off quickly from movement around the bushing.

I countersank mine using the small-head 'oops' rivets. If the rivets weren't flush it looks like there may be some potential interference with the servo push rod..

the only sliding relative motion within the bellcrank assembly would be between the outside surface of the bushing and the inside surface of the bellcrank tube. These surfaces should not be primed. I put some Aeroshell grease on them before assembly.

There's actually another location where some sliding contact is made and that's where the bellcrank tube rests on the lower spar flange. Some suggestions to alleviate that rubbing are discussed in the 'Aileron Bellcrank Washer' thread on this forum