Abstract: An apparatus for producing squared timbers by means of severing portions or boards from opposite surfaces of the log without creating either chips or sawdust characterized by oscillatory opposed banks of staggered blade units with the blades of each unit extending progressively toward the axis of the log as the log passes therebetween. To provide improved surface quality of the boards produced, the apparatus has one of the banks of blades rigidly mounted in a first adjustable carriage and the other bank is mounted in a subframe movable in a second adjustable carriage with the subframe and other bank being urged into engagement with the log under a predetermined contact.