Special equipment is described which was designed and constructed to investigate the distributions of the normal pressures and the longitudinal and transverse shearing stresses along the arc of contact during the rolling of metals between plain cylindrical rolls. While the paper is restricted to a description of this apparatus, it is planned to utilize it in studying the effects of many of the important rolling variables both on the contact stresses and on the resulting mechanical properties of the rolled product. Experimental results will be presented in a later paper.