A horizontal lathe for manufacturing a porous optical fiber preform, the horizontal lathe being configured to hold and fix 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 includes a thermal expansion absorbing mechanism configured to absorb a change in dimension of the target, the change being due to thermal expansion of the target in a direction of the rotation axis.

A tail stock moving mechanism, in which a tail stock that holds a work with a predetermined pressure force is moved by a ball screw and in which control required for holding the work with the predetermined pressure force is implemented, is accomplished in a predetermined order wherein, the tall stock 1 holds a position of the work 5 and is supported by a ball screw 2, torque generated by a drive motor 3 that drives the ball screw 2 is detected, and when the torque reaches a predetermined reference value, then operation of a brake 4 to limit rotation of the ball screw 2 and cutting off of an input from a power supply to the drive motor 3 are performed.

A tail stock moving mechanism, in which a tail stock that holds a work with a predetermined pressure force is moved by a ball screw and in which control required for holding the work with the predetermined pressure force is implemented, is accomplished in a predetermined order wherein, the tall stock 1 holds a position of the work 5 and is supported by a ball screw 2, torque generated by a drive motor 3 that drives the ball screw 2 is detected, and when the torque reaches a predetermined reference value, then operation of a brake 4 to limit rotation of the ball screw 2 and cutting off of an input from a power supply to the drive motor 3 are performed.

A tailstock for supporting a workpiece along a vertical rotary axis includes a base member, and a housing having a wall including a first end, and a second end, an outer surface, and an inner surface defining a central passage extending between the first and second ends defining a longitudinal axis. The second end is coupled to the base member. A workpiece support extends through the central passage. The workpiece support includes a first end, a second end and an intermediate portion extending therebetween. A linear bearing is coupled to the base member in the central passage. The linear bearing slideably receives the second end of the workpiece support. A displacement sensor assembly includes a stationary portion mounted relative to one of the base member and the housing, and a moveable portion mounted to the second end of the workpiece support.

A tailstock for supporting a workpiece along a vertical rotary axis includes a base member, and a housing having a wall including a first end, and a second end, an outer surface, and an inner surface defining a central passage extending between the first and second ends defining a longitudinal axis. The second end is coupled to the base member. A workpiece support extends through the central passage. The workpiece support includes a first end, a second end and an intermediate portion extending therebetween. A linear bearing is coupled to the base member in the central passage. The linear bearing slideably receives the second end of the workpiece support. A displacement sensor assembly includes a stationary portion mounted relative to one of the base member and the housing, and a moveable portion mounted to the second end of the workpiece support.

A method of supporting a rotating member of a tailstock includes rotating a rotating member coupled to a workpiece support slidably mounted in a housing of the tailstock, causing the rotating member to shift along a longitudinal axis in a first direction, and measuring an amount of vertical displacement of the rotating member.

A method of supporting a rotating member of a tailstock includes rotating a rotating member coupled to a workpiece support slidably mounted in a housing of the tailstock, causing the rotating member to shift along a longitudinal axis in a first direction, and measuring an amount of vertical displacement of the rotating member.

A method of processing a workpiece includes supporting the workpiece on a tailstock extending along an axis, thermally processing the workpiece with a processing device, and displacing a portion of the tailstock assembly in response to thermal expansion of the workpiece as a result of processing with the thermal processing device.

A method of processing a workpiece includes supporting the workpiece on a tailstock extending along an axis, thermally processing the workpiece with a processing device, and displacing a portion of the tailstock assembly in response to thermal expansion of the workpiece as a result of processing with the thermal processing device.

A power tool, such as a hammer driver-drill (1), includes: a motor (8); a motor housing (7A) that holds the motor (8); a grip housing (7B) connected to the motor housing (7A); a battery mount housing or enlarged-part housing (7C) connected to the grip housing (7B); and a dial (24) that is provided in the enlarged-part housing (7C) such that it is rotatable about a dial shaft (29). A threshold for stopping the motor (8) is settable by rotating the dial (24).