I picked up a Vickers Martini at Tulsa last weekend and it is missing the rear sight. I do have a PH8 sight that will fit it, but I don't have the screw that holds the sight in. The hollow screw is just over .5" OD with a very fine thread. Does anyone know of where one of these might be found or if not, at least the diameter and thread pitch so that I could make my own? Being an inside thread, I believe it is in the 40-50 tpi range, but that isn't close enough. A .500 rod will slip inside the threads, so it is slightly larger than that. Any help would be greatly appreciated.