They dont "make" a joint. You cant just walk into a store and buy a joint (except in Cali). A joint is the term for where the butt and shaft are "joined" together. In a piloted joint, this usually consists of a joint screw, an insert in the shaft, a joint collar, and trim rings. In a sense, every cuemaker "makes" his own joints because he assembles all of the parts on the cue and gets them to fit together properly. Most of the metal parts, joint collars, screws, and inserts, are outsourced. Those who use materials of bone and plastic can cut and shape them themselves, but they still have to buy the materials from somewhere.
With a piloted joint, some cuemakers take extra time to ensure a tight fit between the shaft pilot and the joint collar.
The only cuemakers I am aware of that have a specially designed joint which no one does are lambros and layani. Most other cuemakers use joint systems that can be duplicated by any other cuemaker, whether piloted or flat faced.
If you are talking about someone who makes his own metal to mold the pin, collar, and insert, I would say no one.
