the hersh wrote:
Are not metal ferruled rods technically butt over tip?
No. The issue is the rod blank diameter on either side of the ferrule.
For a standard metal ferrule rod, the rod blank diameter does not change drastically at the ferrule*. The builder takes a 1-piece rod, cuts it in two, and installs the ferrule. The same thing happens with spigot ferrules and sleeve ferrules - the rod blank diameter does not change drastically.
For a butt over tip ferrule (or a tip over butt), one section of the rod blank must literally fit inside the other. The diameters of the two pieces are dramatically different, so much so that separate rod blanks are used. With a butt over tip blank, the tip section is considerably thinner than the butt. The tip section is therefore much more flexible at the ferrule than the butt. That gives the 'hingey' feeling that only the outer portion of the rod blank is bending.
Tom
* Step down ferrules would give the same effect as a butt over tip glass ferrule, but those are rarely used on glass rods