Abstract: A machined shape of a bore is based on the deformation amount of a data-acquisition bore after fastening of cylinder head. A cross section of an approximate shape is set to be an approximately-true circle shape, and a diameter of the approximately-true circle shape is changed along a central axial direction in accordance with the deformation amount of the data-acquisition bore, to determine the approximate shape. The approximate shape has a cross section having the approximately-true circle shape and has a simple shape which is symmetrical about the central axis. Since the machined shape of the bore is the shape obtained by reversing a phase of a recess and a projection of the approximate shape about a predetermined cylindrical shape, the machined shape has a cross section having the approximately-true circle shape and has a simple shape which is symmetrical about the central axis.

Abstract: A plurality of grind-stone-mounts 12 each having a grind stone 15 on its outer side are attached to a holder 11 of a honing head 10 expandably along a radial direction. Each of the grind-stone-mounts 12 is provided with a support part 13 disposed inside along the radial direction, and a grind part 14 including the grind stone 15 and disposed outside along the radial direction. The grind part 14 is swingably attached to the support part 13 through one or more spring members 16 disposed at intervals along an axial direction of the holder 11.

Abstract: A machined shape of a bore is based on the deformation amount of a data-acquisition bore after fastening of cylinder head. A cross section of an approximate shape is set to be an approximately-true circle shape, and a diameter of the approximately-true circle shape is changed along a central axial direction in accordance with the deformation amount of the data-acquisition bore, to determine the approximate shape. The approximate shape has a cross section having the approximately-true circle shape and has a simple shape which is symmetrical about the central axis. Since the machined shape of the bore is the shape obtained by reversing a phase of a recess and a projection of the approximate shape about a predetermined cylindrical shape, the machined shape has a cross section having the approximately-true circle shape and has a simple shape which is symmetrical about the central axis.

Abstract: A plurality of grind-stone-mounts 12 each having a grind stone 15 on its outer side are attached to a holder 11 of a honing head 10 expandably along a radial direction. Each of the grind-stone-mounts 12 is provided with a support part 13 disposed inside along the radial direction, and a grind part 14 including the grind stone 15 and disposed outside along the radial direction. The grind part 14 is swingably attached to the support part 13 through one or more spring members 16 disposed at intervals along an axial direction of the holder 11.