All of the remaining countersinks in the LH lower spar flange were completed. Using the single flute countersink made it very easy. They cut quickly and leave a very smooth surface. The way to get good results is use an electric drill and push reasonably hard. You start to develop a feel for when it's cutting efficiently similar to the feel you get when you drove a good rivet.
Treated all the CS with Bonderite and called it a night. This section has turned into monotony and I can't wait to finish off the last flange and move on to the flaps.
