Beth Shaut of the Carder Steuben Shop in Corning responds to #610, which follows below if you want to cross reference, or go to the links provided by Gordon Hancock.

Your Tiffany Stemmed are what we call Pillar Ribbed by using a tool to make the grove and not applied to the stem. your last photos are really nice applied threading (very even and exact.

Gordon Hancock, Tiffany pastel collector of Patchogue, NYweighs in.
I have a number of wine and champagne glasses in my collection of Tiffany Pastel glass with stems that I have always referred to as “reeded.” I purchased some of these pieces from Ray Grover and he referred to the stems as reeded. Apparently these stems were extruded through a die as long rods and then cut to the desired length; heated and attached to the base and bowl of the piece. I believe the term reeded refers to a piece that has been extruded, photo 1&2.


Notice how the stem has turned opalescent when reheated to be attached to the base.

Threading is just that, threads applied to the surface of a piece, whether done with a machine or by hand. Threading is often applied to a gather and then marvered down into it. Then the gather is blown out. Many pieces of Libbey Nash were done in this manner, photo 3.
http://www.pixclix.com/Tias/Unknown-3.jpeg

In the Libbey Nash case the glass is crystal and the colored threading infuses the piece with color giving the appearance that the piece is colored.

Some pieces of Libbey Nash were blown out and then the threading applied to the surface and remain in relief, photo 4&5.


Apparently all this threading was done by machine.
Just my opinion.