One of the important steps in the manufacture of glass by the float process is the control of glass thickness by stretching the ribbon. The first step in a program to model the stretching of float glass is discussed. A simple, 1‐dimensional analysis is presented for the mechanics of stretching a free ribbon, i.e. one without edge constraints in the stretching region. For the case of a stiff (“cold”) ribbon, the present analysis yields closed‐form solutions which are generally valid but do not encompass all phenomena of interest. The stretching of a “hot” ribbon is, therefore, treated quantitatively by computer simulation. This approach is used to illustrate the differential attenuation of the width and thickness of hot ribbons. In another numerical example, the caculated width attenuation is compared with the results of in‐plant