Abstract: Provided is a method of manufacturing an elbow, including: a first cutting step of cutting a material by relatively moving a cutting section of a cutting tool, which is formed of at least a part of a substantially spherical shape, along an inner side surface of the elbow to be finished in a direction from a first end surface to a second end surface of the material; and a second cutting step of cutting the material by relatively moving the cutting section along the inner side surface of the elbow to be finished in a direction from the second end surface to the first end surface of the material.

Abstract: A hole is formed in an elbow through the steps of: forming a starting hole in a material, the starting hole having an undercut remaining on a hole surface; finishing an inner diameter of the starting hole (11-3) on one end side by revolving a side cutter (II) including an arc-shaped cutting edge and having an outer diameter smaller than a finishing hole diameter while rotating the side cutter (II) in such a posture that the side cutter (II) is inclined in a predetermined direction relative to the material (12), the revolving being carried out so that the side cutter moves along a hole surface to be finished; and finishing the inner diameter of the starting hole (11-3) on another end side by revolving the side cutter (II) while rotating the side cutter (II).

Abstract: Provided is a method of manufacturing an elbow, including: a first cutting step of cutting a material by relatively moving a cutting section of a cutting tool, which is formed of at least a part of a substantially spherical shape, along an inner side surface of the elbow to be finished in a direction from a first end surface to a second end surface of the material; and a second cutting step of cutting the material by relatively moving the cutting section along the inner side surface of the elbow to be finished in a direction from the second end surface to the first end surface of the material.

Abstract: A hole is formed in an elbow through the steps of: forming a starting hole in a material, the starting hole having an undercut remaining on a hole surface; finishing an inner diameter of the starting hole (11?3) on one end side by revolving a side cutter (II) including an arc-shaped cutting edge and having an outer diameter smaller than a finishing hole diameter while rotating the side cutter (II) in such a posture that the side cutter (II) is inclined in a predetermined direction relative to the material (12), the revolving being carried out so that the side cutter moves along a hole surface to be finished; and finishing the inner diameter of the starting hole (11?3) on another end side by revolving the side cutter (II) while rotating the side cutter (II).

Abstract: Provided is a method of manufacturing an elbow, including: a first cutting step of cutting a material by relatively moving a cutting section of a cutting tool, which is formed of at least a part of a substantially spherical shape, along an inner side surface of the elbow to be finished in a direction from a first end surface to a second end surface of the material; and a second cutting step of cutting the material by relatively moving the cutting section along the inner side surface of the elbow to be finished in a direction from the second end surface to the first end surface of the material.

Abstract: A hole is formed in an elbow through the steps of: forming a starting hole in a material, the starting hole having an undercut remaining on a hole surface; finishing an inner diameter of the starting hole (11-3) on one end side by revolving aside cutter (II) including an arc-shaped cutting edge and having an outer diameter smaller than a finishing hole diameter while rotating the side cutter (II) in such a posture that the side cutter (II) is inclined in a predetermined direction relative to the material (12), the revolving being carried out so that the side cutter moves along a hole surface to be finished; and finishing the inner diameter of the starting hole (11-3) on another end side by revolving the side cutter (II) while rotating the side cutter (II).

Abstract: Provided is a method of manufacturing an elbow, including: a first cutting step of cutting a material by relatively moving a cutting section of a cutting tool, which is formed of at least apart of a substantially spherical shape, along an inner side surface of the elbow to be finished in a direction from a first end surface to a second end surface of the material; and a second cutting step of cutting the material by relatively moving the cutting section along the inner side surface of the elbow to be finished in a direction from the second end surface to the first end surface of the material.

Abstract: A hole is formed in an elbow through the steps of: forming a starting hole in a material, the starting hole having an undercut remaining on a hole surface; finishing an inner diameter of the starting hole (11?3) on one end side by revolving a side cutter (II) including an arc-shaped cutting edge and having an outer diameter smaller than a finishing hole diameter while rotating the side cutter (II) in such a posture that the side cutter (II) is inclined in a predetermined direction relative to the material (12), the revolving being carried out so that the side cutter moves along a hole surface to be finished; and finishing the inner diameter of the starting hole (11?3) on another end side by revolving the side cutter (II) while rotating the side cutter (II).