To match drill the thing you'll have to take the tail-spring off the plane. Take the old spring over to the drill press and send the drill bit (stopped) through the hole. While it's there, fix the tail spring in this position using whatever clamp/jig/fixture you can devise. Retract the drill, slip on the new swivel assembly, poke the new hole. Done deal.
Fullerton, Ca. w/beautiful 2.5 year old son
RV-4 99% built
Rag and tube project well under way
paid =VAF= dues through June 2013