My name is Stuart Webber and have been testing austenitic gen. end rings for almost 20yrs. Being employed by the then electricity generating board I have tested every end ring, a number of times, on every generator set owned by the electricity board in Queensland Australia. I have plenty of tales to tell but simply state " if you are new to the game, and have not considerable ultrasonic experience, you are heading for a fall in trying to test these troublesome items. I have seen many end rings removed to verify restults or as a result of underlying conductor or insulation repairs. I have rejected a few and have a collection in my laboratory with some great defects, and still scratch my head at times when testing these things. There is a lot of paranoia about crack growth rates and micro defects allowed but on a practical level you should see the size of some of the defects that have survived service conditions, and I know that I wil cop some flak over this statement but it is fact. I gave away the manual methods of testing these items as I have prooved over the years they fall down especially where the underlying structures impinge on the inner surface of the ring which produces a strong return signal anyway. I have been using the AEA time of flight equipment for the last 4 years and am very pleased with the results. Again I know I will cop flak for this statement as there is great controvesy over the correct method to use on these items but my business is at the sharp end, not the laboratory and I have seen and done enogh to prove to myself which is the way to go ie conventional or TOFD. Be assured of one thing, if you attempting to test these items with no specific training on them you are heading for a fall.