Originally Posted by scard
Yep. I use old pieces of bicycle tube.
hadn't thought of that. i was going to put some tape on my bar, but as i live about a block from a hardware store, i figured... why not an o-ring?!
i got some that were just a little wider than a set -3 rivet shop head (the rubber compresses while riveting) and i just set about 75 rivets without a single bad rivet! the two o-rings stabilize the bar and keep it flush against the flange i'm riveting, space it far enough to prevent marring, and allow me to kind of just hold it there loosely against the web/flange (it orients itself)