Rheological properties of the flakes of poplar and oak woods cut with knives of various rake angles were studied by applying the method of parameter separation. The main results obtained were: 1) Rheological properties of the flakes were affected by rake angles of the knives with which the flakes were cut 2) Change of the flake properties made by the increase of rake angle was advantageous to board properties. 3) Effects of rake angle on flake properties were basically in commom for different wood species, while it is possible that the effects displayed on board properties vary with various species.