The Zenair supplied rivets are ~1/8" shorter than the specified length for 3/16" rivets through the spar cap joint. It turns out that the Zenair Construction Standard #403 are less demanding that the corresponding Mil Spec standards (see 5/27/10 log entry). The Zenair supplied rivets would require significantly less driving than the longer rivets that I used for practice. It is entirely possible that, using the shorter Zenair rivet length, I would have been able to produce shop heads meeting the Zenair Standard with my 3X rivet gun. There is no question in my mind that a 4X gun would do a better job and require fewer hits, but a 3X gun may well have been usable with the Zenair supplied AN470-AD-6-14 rivets.
