The present paper presents main assemblies of a machine for rolling wooden elements. The design of the assemblies directly influences parameters, which are responsible for geometrical characteristics of wood plasticisation. These parameters include: roller temperature, strength and duration of force exerted on the surface of the plasticised material. Thus, the assemblies are responsible for: adjusting the roller surface temperature, adjusting gap between the rollers and drive transmission. The parameters of wood refining process were identified on the basis of conducted theoretical analyses and, subsequently, they were used to design the machine. The solution of the formulated problem was found on the basis of the Hubera-Misesa-Hencky's hypothesis of ultimate energy of non-dilatational strain. The aim was reached by solving a set of plasticity equations for porous and orthotropic layer, by developing a formula for calculating critical stresses. As a result, we have obtained an illustration of time-dependent stress distribution in the direction towards the interior of a layer of wood under a hot rotating roller, for specific surface temperatures.