I saw the assembly of a high temperature Boiler Code application the other day. They used nickel and Chrome alloys for the high temperatures. I found the flanges to be particularly interesting. They were using UNF threads, which is not common in boilers, and they were using threaded rod with nuts on both ends. So I talked with the design engineer. He had called out hex bolts on the drawing, but approved the change because they had a long lead time and were much more expensive. He also said that he likes the threaded rods better anyway because they are stronger, because they eliminate a KT between the shank and the head. He used the UNF threads only because his customer was in love with them. Have any of you ever considered this KT in one of your designs?