| 摘要 |
Forming a process reference hole and a process reference plane by applying provisional processes to a small diameter hole 2 and to a side of a connecting rod 1, and simultaneously finishing the small diameter hole 2 and the large diameter hole using said process reference hole and the process reference plane to guarantee a position and allowance of the large and the small diameter holes. Further, at the time of applying the process to make the small diameter hole 2 as the process reference hole, a deep spot facing 5 is formed.When cutting the small end 3 to a given width at a final mechanical process, one portion of the deep spot facing 5 is exposed to become a chamfered portion of the small diameter hole 2. Further, at the final process, the processing where on an inner wall of the small diameter hole burs are generated is not carried out to deteriorate the dimension precision. <IMAGE> |
