Fig. 8
From: Wood machining with a focus on French research in the last 50 years
Evolution of friction angle with cutting speed for green wood (chestnut) at 2 temperatures (from Thibaut 1988). It should be noted that the bottom left of the graph is not a true origin (neither the ordinate nor the abscissa is zero), but the axes are shown intersecting by commodity; abscissa (cutting speed) is used in logarithmic scale, but the actual values are put in legend