Abstract: An external thread member capable of performing a fastening operation efficiently without increasing the number of parts by assembling a collar into the external thread member. The external thread member 1 includes a shaft portion 5 inserted into a mounting hole 105 of a mounting member 101 through a collar 7, and the mounting member 101 is fastened to a fastening member 102. The shaft portion 5 includes a threaded portion 51 and a neck portion 52. The collar 7 is mounted on the neck portion 52 so as to be rotatable relative to each other and is engaged with the threaded portion 51 whereby retention is achieved. A counterbore hole 106 is formed in an opening close to the mounting hole 105 of an internal thread hole 104 with a tubular portion 71 inserted into the mounting hole 105 of the collar 7.

Abstract: An external thread member capable of performing a fastening operation efficiently without increasing the number of parts by assembling a collar into the external thread member. The external thread member 1 includes a shaft portion 5 inserted into a mounting hole 105 of a mounting member 101 through a collar 7, and the mounting member 101 is fastened to a fastening member 102. The shaft portion 5 includes a threaded portion 51 and a neck portion 52. The collar 7 is mounted on the neck portion 52 so as to be rotatable relative to each other and is engaged with the threaded portion 51 whereby retention is achieved. A counterbore hole 106 is formed in an opening close to the mounting hole 105 of an internal thread hole 104 with a tubular portion 71 inserted into the mounting hole 105 of the collar 7.

Abstract: A method is provided for manufacturing a cylinder for an internal combustion engine, which makes it possible not only to manufacture the cylinder by a high-pressure die casting method at low cost and in high precision, but also to prevent relative misalignment among the scavenging port, suction port and exhaust port of the cylinder. This method is characterized by the steps of: preparing a cylinder liner made of an aluminum alloy pipe and provided with the scavenging port, and a bore-core die as well as cores for scavenging ducts both being uncollapsible and configured so as not to intrude into the scavenging ports; setting the cylinder liner in place in the bore-core die; and casting, by means of metal mold casting method, an aluminum alloy onto the outer peripheral surface of the cylinder liner to thereby mold a main body of the cylinder.