Funny you should be asking about this. The December 2004 issue has a section on special clamping needs and solutions. Do you attach the strips before the other parts? If so, apply an nice coating of Glue(Titebond III is the strongest of the family and sets the quickest), then tack the strips in place with some brads. Instead of clamps try setting some 2x4's across the strips and placing books or other heavy objects on them. This will hold the strips tight enough for the glue to do it's job, it only needs enough pressure to hold the pieces together. Then glue your bin sides and tack them in place. This time use something like a piece of plywood on top of your bin sides and place weight on it. As an alternative you could also just run 2 screws into each bin side from the back, counter sinking them so they are flush. This would be stronger but I think it is probably overkill.