What is the difference between a full thread bolt and a half thread bolt?

The length of the bolt thread is different, the length of the screw is all threaded, and the screw of the half threaded bolt is divided into two parts, one part is the thread and the part is light. Full threaded bolt can be screwed to the end and half threaded bolt can only be screwed to the threaded part. In addition, when processing the bolts, the half-threaded bolts can reduce the workload and save the cost without affecting the use.