Posted by:
Mike L Clark (---.range86-162.btcentralplus.com)
Peter look at The Complete Automobilist website
[
www.completeautomobilist.com] part no 422 has a 19mm thread - very likely really 3/4 inch.
Also part no 254 and 253S
They have a lot of versions, some of which you might be able to adapt.
Mike