Horizontal lathe

A horizontal lathe for manufacturing a porous optical fiber preform, the horizontal lathe being configured to hold two opposite ends of a target in such a manner that a longitudinal direction of the target is a substantially horizontal direction, and cause the target to be rotated around an axis parallel to the longitudinal direction thereof as a rotation axis, the horizontal lathe comprising:

• a first chuck jaw configured to hold one end of a target and be rotatable about the rotation axis;
• a second chuck jaw configured to hold another end of the target and be rotatable about the rotation axis;
• a chuck block fixed to the second chuck jaw, the chuck block having a protruding part provided on one side thereof that is opposite to another side thereof to which the second chuck jaw is fixed;
• an axle receiving part including a recessed part, the recessed part configured to allow the protruding part of the chuck block to move therewithin;
• a spring that links a surface of the protruding part that faces the recessed part with a surface of the recessed part that faces the protruding part;
• and
• a bearing provided between an inner circumferential surface of the recessed part of the axle receiving part and an outer circumferential surface of the protruding part of the chuck block, the bearing configured to allow the second chuck jaw and the chuck block to move in a range of motion that spans between the surface of the recessed part that faces the protruding part and the surface of the protruding part that faces the recessed part,
• wherein the recessed part, the protruding part and the bearing form a thermal expansion absorbing mechanism that absorbs a change in dimension of the target, the change being due to thermal expansion of the target in a direction of the rotation axis.