Thanks Dave,after all these years collecting I never knew these bowls,and I've seen lots,were meant to have frames in fact I don't remember ever seeing one.Davidson would never have crossed my mind I always thought of Stourbridge for this type,suppose being local I'm a bit biased,what do you make of 'opalescent one';I'm due to fetch a couple of threaded opalescent bowls in a week or two,if they are still there, I'll post them if possible,thanks again,Keith