[ghford]

Many thanks for all of the varied opinions on this and remembering that I am the one asking for help, will not disagree with any regarding proceedure. I will though comment on the nature of the product which seems apparent and go along with what Chris indicates regarding the high carbon content of these recently installed like new studs. They are harder than hard and brittle, just like iron which is why I believe it twisted off as I was conscious of not applying too much pressure. Manifold studs are commonly drilled out that have been subject to heat for years, but are good low carbon processed steel with a softened flexibility. Why anyone would make/sell studs this hard and brittle is beyond me. A good study here and lesion should be to test hardness and if like these, discard. To add to the opinions, just got a call back from a welder who indicated "TIG by one who really knows it, not me".