Riveted chain is constructed using pins that extend through the plate on each side and are then riveted, or sidemashed, on their ends to add some additional strength to the hold between the pin and plate. Note: the riveting, or sidemashing, is NOT what holds the pin and plate together. The interference fit between the plate hole size and the pin diameter hold the two together.
Cottered chain is constructed using pins that extended through one plate and are sidemashed and through the second side a further distance than through the first plate, with a cross-drilled hole for inserting a cotter pin. Note: cottered chain is also manufactured using an interference fit between the plate hole size and pin diameter. However, the plate is easier to remove following removal of the cotter, because grinding of the riveted pin end is not necessary.