Ok folks maybe ya'll can help me out here. About 25 years ago when I was working on donut makers a lot we had a 3 jaw chuck system that was comprised of three base jaws with interchangeable shells in different sizes and shapes. We had square, hex , and round. Just unbolt the shells from the jaws and replace with whatever jaw you needed next. What I can't remember is if these was made in house or purchased. Also I can't remember what they was called. This was a long time ago in a period of my life where I was doing a lot of things after work I shouldn't have, (clean 20 years now), so my memory of that time is sketch at best. If it will help I can through together a rough idea of them in SW.