Clamshell pipe lathe having improved bearing arrangement

An improved bearing and race structure for a clamshell machining lathe used in finishing pipes comprising:

• (a) a first, stationary annular member adapted to be concentrically clamped about the periphery of a cylindrical pipe segment to be finished, the first annular member having an inner arcuate face, an outer arcuate face and a planar surface extending therebetween;
• (b) a plurality of roller bearings rotatably mounted on individual axles and having a predetermined outer diameter, the roller bearings being affixed to the first annular member with the axles thereof perpendicular to the planar surface of the first annular member to define a generally circular track;
• (c) a second, rotatable, one-piece annular member having an inner arcuate face, an outer arcuate face and a planar surface extending therebetween, the outer arcuate face including gear teeth thereon, the planar surface of the second annular member including a circumferential groove having opposed parallel walls defining a bearing race of a depth and width to receive said plurality of roller bearings defining the generally circular track therein when the first and second annular members are juxtaposed with the planar surface of the first annular member in facing relationship to the planar surface of the second annular member, the predetermined outer diameter of the plurality of roller bearings cooperating with the opposed parallel walls defining the circumferential bearing race to rotatably support the second annular member relative to the first annular member.