Choose rivet of the correct diameter to match diameter of punched hole.

Choose rivet of correct length deduced from the combined thickness of the metal pieces. As a rule, the end of the rivet should be longer than the combined thickness of the metal to be joined (approx 2mm-3mm in the case of joining lengths of lighter gauge materials up to 3mm thick or approx 3mm-5mm in the case of joining thicker sections up to 5mm thick).