Fully automatic machines such as automatic turret lathes and automatic screw machines are programmed to do a sequence of machining operations to make a completed product. Aotomatic turret lathes usually are programmed by numerical control(NC)on punched tape. Automatic screw machines,used for high production of small parts,are typically programmed with cams, although some are numerically controlled. There are several types of automatic machines:the single spindle machine, the sliding head(or Swiss type), the multiple spindle,and the revolving head wire feedtype. Multiple spindle bar and chucking machines are high-production turning machines that can do a variety of operations at different stations.