For what I need because they are a bit hard to come by. One inch stock is what I use and I have to tie the corners together. This is also the most latitude these clamps occupy. Once tightened they hold up very well and you can adjust the connection a bit so they line up better after tightening. Nothing else I've tried has worked either. Like I said, they're a bit difficult to get along with, but I think I can forgive that as they're better at their job.