3 hours
Machine countersank (sunk?) HS-902 front elevator spar and started on HS-903. I test fit them with the skins (of course) and there was daylight between the spar flange and the dimpled skin. Don't like that.
Read through the Van's instructions (they said countersink should be .05" deeper than an AN426 (got your Mk.8 eyeballs calibrated???). Dan Checkoway's excellent sheet metal series was similar. I figured a skosh more than flush sounded about right, but still wondered.
I sent Jeff Moreau an email (our chapter sheet metal tech counselor, rivet guru, flight instructor, hawker pilot, and builder of a gorgeous RV-8a). He said you definitely don't want to go too shallow, and suggested just a smidge deeper than flush.
He was also offered to inspect my test piece and give me a riveting demo if I'd drop by his hangar tomorrow. Twist my arm. Always looking for an opportunity to learn. I'll be out at CPK tomorrow anyway working on 08Tango after our annual.
