I make speaker cabs, usually for "Big noise", eg, big cabs. I have the eminence cab builders book with all the tech detail, some are for "speaker stand mounting" thomann prices for all the cab extras, handles, corner protectors, speak ons, Jack's and these 36mm stand flanges, are pretty good. I always use them and even carry spare pieces to repair other people's cabs.
Before Thomann, this sort of fitting took months to aquire and to pay for:-/