In this study, we carried out basic orthogonal cutting in the LR plane by changing the fiber orientation from 0 degrees to 90 degrees in the cutting plane. We measured dimensions before and after cutting, and after swelling of the chip. We investigated the influence of fiber orientation in the cutting plane, depth of cut and cutting angle on dimensional change by cutting as well as by swelling after cutting. The results can be summarized as follows: (1) The ratio of cut to uncut length in the cutting direction decreased with increasing depth of cut as well as with decreasing cutting angle regardless of fiber orientation on the cutting plane (phi (2)). (2) The swelling coefficient of chips in the cutting direction decreased with increasing depth of cut as well as de creasing cutting angle, regardless of fiber orientation in the cutting plane. The swelling coefficient increased slightly with increasing fiber orientation (phi (2)) in the region of from 0 degrees to 70 degrees and increased rapidly with increasing fiber orientation in the region from 70 degrees to 90 degrees. Chip thickness increased by swelling, and this swelling tended to increase somewhat with increasing fiber orientation in the cutting plane. The swelling coefficient in the chip width direction was lower than in the above two directions, and the swelling coefficient changed from 4% to 0% with increasing phi (2) from 0 degrees to 90 degrees. (3) The swelling coefficient of chips in the cutting direction increased linearly with increasing ratio of cut to uncut length, and this was highly correlated. Equation (6) expresses the relationship between the swelling coefficient of the chip (beta ' (c1(phi2))), the ratio of cut to uncut length (delta (c1(phi2))), the swelling coefficient of the wood (beta ((phi2))), and the ratio of unrecovered length of the chip in the maximum swelling condition (U-c(phi2)) (4) The length in the cutting direction recovered by swelling of the shrunken chip and the length of the swollen chip (distance from A to B) were greater than the initial length before cutting in the LIZ plane under 0-90 cutting and were less than the initial length under 90-0 cutting. (5) U-c(phi2) is the ratio of unrecovered length of the chip under the maximum swelling condition, and it has an influence on surface degradation.
