Abstract: A ring type debarker in which the arm carrying section is mounted for rotation on a centrally disposed, tube-like member through which the logs pass while being debarked. The central support member is supported in cantilever fashion from the outfeed end thereof. Mounted for rotation with the arm carrying section are means to circulate oil through the main bearing which supports the rotary parts and an air compressor and a receiver for the same. Each arm is equipped with expansible flexible bellows-like air bag members for holding the tool ends of the arms in log engaging positions. The compressor and pump are driven by means of a ring gear mounted on the ring support member, the pump and compressor in turn carrying pinions in mesh with said ring gear.