So how did at least one builder dimple and rivet the battery box? Short answer: ALLIGATOR. With its flush rivets heads on the inside, assembling the battery box can present an uncommon challenge yet mine proved to be just one more in a long line of reasons why 95% of the time I prefer using an alligator squeezer over the far more common "C" type. Using it, I was able to take advantage of the lightening holes to access some of the rivets.......How did you dimple/counter sink and then rivet the battery box to the mounting brackets with the flush heads on the inside of the box?
What he said.drill a hole in a bucking bar that will hold the male dimple die. The female die goes in the rivet gun. Brrrrrrrp, dimpled.
Now use the flat side of the bucking bar and a back-rivet tool in the rivet gun.
Brrrrrrrp, done!