The Effect of Spiral Grain on Energy Requirement of Plane Milling of Scots Pine (Pinus sylvestris L.) Wood

The effect of spiral grain angle on the cutting power was tested during plane milling of Scots pine wood. It is known that cutting resistance depends on the arrangement of grain in relation to the direction of woodworking operations. In this work, up-milling (conventional cutting) was applied, as well as two woodworking techniques: with the grain and against the grain. Tests were conducted on samples differing in their position at the stem cross-section, one located closer to the circumference with the spiral grain angle of 11.5° and the other located closer to the pith, in which the spiral grain angle was 7.5°. This analysis confirmed significant differences in cutting power recorded for different values of spiral grain angle and depending on the applied cutting techniques. Cutting power at milling with the grain was greater than at milling against the grain. For samples with a smaller spiral grain angle a lower cutting power was recorded than for samples with a greater spiral grain angle. Differences in cutting power requirement between milling with the grain and against the grain increase with an increase in spiral grain angle.