I'm getting more interested in older LF cameras and some of the weird and wonderful barrel lenses out there. The trouble is that many of the lenses no longer have their lens mounts. If I could make my own it would make life a lot easier. The specifics that I am confused about are whether the normal thread cutting function is suitable for putting a thread on the inside surface of a ring and whether there are size limits to this. I'm think of a mount for things like Aero lenses and old brass lenses that may have a 3-4" inside diameter and need a 5" outside diameter. The lathes I have (very briefly) looked at have specs based on "centre height", "swing over bed", "swing over carriage" and "distance between centres". Which of these will be the crucial ones? I've also seen a few combined lathe and mill set ups. Is this a good idea or should I stick to two separate tools?