Abstract: This process of chipping logs to manufacture lumber is different from most other wood-cutting processes.The main characteristics of the former are that it not only requires to have a flat surfaces of the lumber,but also to have the appropriate sizes of chips;besides,it requires that the chips can not be deformed too greatly.In order to meet the above-mentioned requirements,mimicking the practical working conditions of chipping,we mounted the contricted chipping head on our reformed four side moulder to make the experiments in the cutting properties of the head. This article analyses the chipping kinematics,and on the basis of this analysis,it deals with the approximate formulars for calculating the thickneess and length of the chips.The width of the chips can be controlled by adopting grooving knives,the grooves positions of them are alternatively arranged on the head.For avoiding that the chips are deformed too greatly,we may increase the rake angle to 50°,and then it will cause the strength of cutting dges to decrease and the friction of the clearance surfaces of knives to increase.So long as a bevelled surface is ground on the clearance surface of each knife,the above-described faults can be eliminated.