My FS 7x17 has its standard 1/4 - 20 female tripod screw receptacle. I would like to add an additional 3/8 - 20. What might work best would seem to be the same style as the existing 1/4 - 20. That is, a brass insert with threads on the outside that was screwed into the wooden base. I am guessing the 1920 mfgr. simply drilled a hole into the base, then with a big T-wrench/ male driver affair threaded into the 1/4 threads and screwed the thing into the base. Can someone tell me who might have such a 3/8 - 20 gizmo? A mere "T-nut," of course, is not what I am looking for. Thanks guys (and CJ)!