Thanks boBA. I read it was an Englishman (can't remember his name, probably in Stourbridge:) who came up with a threading machine and emigrated to the USA, i guess it quickly caught on all over. I saw a lovely nailsea vase with clear threading the other day. I'd never seen such a thing before, it was only a photo but it took me awhile to work out how it was made, with it clear glass threading. Amazing.