I had a suprisingly large number of bad rivets, 22 out of 60 had to be drill out, most due to off center shop heads. I noticed almost all of those were on the holes next to the angle flange. I was resting the bucking bar on the flange as I bucked the rivet and I believe the impact not only bounced the bar back but up as well. Therefore the bucking bar was making a circular motion driving the head off kilter.
So, I drilled off the head and pin punched the shanks out, with a couple needing a small pilot hole drilled to relieve pressure. On one of those the hole got slightly oval. Milspec allows the hole to be as large as a #18 drill and stay with a 5/32 rivet so I think I can avoid an oversize rivet there.
AN bolts arrived today so I can ditch the hardware store stuff.
