The air compressor connecting rod copper sleeve (Fig. 1) processed by our factory has 4 oil grooves in the inner hole. In the original small batch production, the oil groove was pulled out on the lathe with a bore cutter. The four oil grooves pulled out were difficult to be evenly distributed, and the surface roughness did not meet the requirements of the drawings, which was laborious and time consuming. Later, we improved the processing technology and adopted the lathe milling oil tank. The specific method: in the CA6150 lathe, remove the small carriage and the tool holder, install an indexing head, and adjust the points through the backing plate.