Abstract: Articles which nest, such as baking pans, are assembled into a stack by a two-stage lift mechanism in which the assembly of a second stack is commenced while a previously assembled first stack is being discharged from the stack forming apparatus, so that the flow of pans into the apparatus need not be interrupted. Articles such as pans are fed in succession into a stacking station at which the articles are aligned with a vertical path and then dropped. A first stage lift receives the articles and is lowered one step upon the receipt of each article until the first stage lift is lowered to a transfer station. At the transfer station, support of the stack of articles is transferred to a second stage lift which is similarly lowered one step upon the addition of each subsequent article to the stack until a preselected number of articles have been accumulated in the stack.