Abstract: A method of shaping elongate cylindrical structural members so they can be interfitted to build walls or similar structures which uses the natural shaping of the member in interfitting surfaces and involves the cutting of diametrically opposed grooves in the member, each groove involving a single cutting operation and being similarly shaped so as to co-operate with a similar groove and the adjacent circumferential area in other members such that when interfitted to form a wall the logs resist lateral forces.