1. Rough machining stage

The rough machining stage is also the machining stage before the connecting rod body and the cover are combined: it is mainly the machining of the reference surface, including the machining of the auxiliary reference surface, and the machining of the connecting rod body and the cover, such as milling and grinding of the two mating surfaces.

2. Semi-finishing stage

The semi-finishing stage is also the machining after the connecting rod body and the cover are combined, such as fine grinding of two planes, semi-finishing of the big head hole, chamfering of the hole mouth, etc. In short, this is a large finishing. Prepare the small head hole stage.

3. Finishing stage

The finishing stage is mainly to ensure that the main surface of the Bare Engine. All small holes meet the requirements of the drawing, such as honing the big head hole. Fine boring of the small head bearing hole, etc.