Abstract: In the assembly of vibration body, the first width in the lateral direction (X axis direction) is greater than the second width in the longitudinal direction (Y axis direction) in the cross sectional form perpendicular to Z axis of the first portion on the tip side from the closest node position, thereby, the rigidity of a vibration body main part in the X axis direction can be enhanced, and lateral bending vibrations on fixing portion can be restrained. Consequently, an object can be processed highly accurately by the assembly of vibration body that is controlled with a high precision.

Abstract: In a cutting tool, a shank is a support member made of ceramics and although it is light, it is hardly bent. Further, a processing tip made of a diamond having a cutting edge and is fixed to the tip portion of the shank by an active metal method or brazing. The shank is fixed so as to be pressed to the bottom surface of a slit-shaped groove formed in a fixing portion by a fixing screw and a washer. In this case, the washer is a ring-shaped member transforming as a cushioning member and prevents the fastening stress by the fixing screw from locally concentrating.

Abstract: In the assembly of vibration body, the first width in the lateral direction (X axis direction) is greater than the second width in the longitudinal direction (Y axis direction) in the cross sectional form perpendicular to Z axis of the first portion on the tip side from the closest node position, thereby, the rigidity of a vibration body main part in the X axis direction can be enhanced, and lateral bending vibrations on fixing portion can be restrained. Consequently, an object can be processed highly accurately by the assembly of vibration body that is controlled with a high precision.

Abstract: A high-hardness rubber composition which is obtained by vulcanizing an unvulcanized rubber composition comprisingan unvulcanized ethylene..alpha.-olefin rubber composition (A) comprising 100 parts by weight of an ethylene..alpha.-olefin copolymer rubber, 60-150 parts by weight of a reinforcing agent and 0-70 parts by weight of a softener;5-40 parts by weight of a solid diene rubber (B) based on 100 parts by weight of said ethylene..alpha.-olefin copolymer rubber; and4-15 parts by weight of sulfur (C) based on 100 parts by weight of said ethylene..alpha.-olefin copolymer rubber,wherein said unvulcanized rubber composition is obtained by adding said solid diene rubber (B) and said sulfur (C) to said unvulcanized ethylene..alpha.-olefin rubber composition (A).