Click on thumbnail
for larger view
This angle piece is also one that gets bolted and riveted. The second picture shows the flush rivet side. The bolt heads here are not flush because the mating piece will slide right on by it. However, the piece will come so close that the hex heads are indexed with a flat side on top.  If it had one of the points straight up it would interfere with the mating piece.
      These are two more bolted on pieces.