Unmasked oil door and opening; separated door and hinge strap. Match drilled rivet holes through door hinge strap and oil door. Removed all masking tape from Skybolt flanges and inserts. Cleco hinge straps; tape rivets in place to locate Skybolt flanges and inserts. Tape oil door closed; tape inserts down and match drill #30 holes through inserts and oil door. Disassemble hinge; reassemble with spring, remount to top cowl and test function of oil door and hinge.