Cutting forces during drilling of thermally modified ash wood. Influence of thermal modification of ash wood on cutting forces during drilling was anylized in this work. In experiments there were made through holes for differentiate cross sections (for horizontal and vertical placement of annual rings) by means of CNC machine. Simultanously, there was carried out acquisition of thrust force and torque signals with measuerement chain equipped with piezoelectric sensors. Results proved increase of thrust force and decrease of torque during drilling of ash wood which was thermally modified.