AbstractThe aim of the present study was to determine the surface roughness of heat-treated Scots pine (Pinus sylvestris L.), Eastern beech (Fagus orientalis L.), Uludağ fir (Abies bornmülleriana Mattf.), and sessile oak (Quercus petraea L.) wood material samples following planing by the cutters of a horizontal milling machine. The samples that were heat-treated at 140 ºC or 160 ºC for 3, 5, or 7 hours were then processed by star blades or razor blades, which are the most frequently used blade types in a milling machine. The surface roughness of the samples was determined by a touch (spined) scan device (TIME TR200), as indicated by the ISO 4287 principle. The results of the study indicate that heat treatment decreases the surface roughness value of the wood material and a significant difference in surface roughness cannot be detected between planing using the razor blade or the star blade.