Originally Posted by monocoque
What what grip range do I ask for when purchasing 1/8 and 3/16 rivets? The guy behind the counter tells that the grip range is determined by the material being fastened?
What grip range you use, is almost secondary, just so that it is equal to, or better.
In the case of pop rivets, space permitting, to put 2, .032 (.064) total thickness sheets together, you can use 1/8, 3/16, 1/4, 5/16, 3/8 or 1/2 inch grip range. They will all do the same job.
In the case of buck rivets, the situation changes to some degree, but the basic idea is the same.
If, as an example, you want to put the same two sheets together, that total .064 inches, using 1/8 inch diameter buck rivets, you can use 3/16, 1/4, 5/16, 3/8, 7/16, 1/2, 9/16, 5/8, 3/4, 13/16, 7/8, 1", 1 1/4, 1 3/8" grip range.
If what you have is way too long, simply cut them with diagonals.
Obviously, to some degree, the longer the rivet, the more expensive, but not necessarily so, as it also depends on it's popularity.
The best way, is determine the greatest thickness you will be dealing with, and get rivets for that thickness. As you need shorter rivets, simply cut the shank down to the length you wish. Or, get a couple of different sizes.
We use three sizes of 1/8 buck rivets, if you wish, small, medium and large.
Small = 4-6, medium 4-10 and large 4-16.
The # 4, is the diameter in 32'nds, just like the pop rivets.
Of course we also use, for a variety of reason, # 5 and # 6 diameters, in various lengths, as well.
Then, if you wish to toss more rivets into the pot, do you want to use soft rivets that have a tensile strength of 16,000 psi, or perhaps heat treated rivets that have a tensile strength of 38,000 psi?
But we suggest that you follow the old mechanics rule of, KISS.
Your not rebuilding a super sonic aircraft or a jet liner, but just a nice Airstream.