Thanks for the "riveting" info. flyboyj....I probably haven't explained myself very well....the reason I need to know the size of the finished rivet head, is that I am building a largish scale model of the 335 which requires me to stamp some litho plate with mock rivet heads....and to be close to scale, I just wondered what the majority of the rivet head sizes would be on such an aircraft. Someone has suggested about 7mm flush rivet head dia.........just thought I would pose the question here as there seems to be alot of people who know alot of stuff......thanks all the same, abeltasman.