Abstract: A machine for assembling a button shell and button back which features a pair of feeders for advancing shells and backs to a locating and closing station and a mandrel movable from a locating jig to an overlying locating head for registering a shell within a die therein, and power means for driving the die and shell into a closing die of the jig for crimping the shell about a button back to form a finished button. A method of assembling buttons is disclosed including steps of nesting a button shell and button back, engaging the shell of a nested shell and back within a shell locating die in precise registration therein, and then closing the shell onto the back by compressing the nested shell and back between the shell locating die and a closing die.