Tandem drawing is the drawing force of the process through two dies in tandem was evaluated by being compared with the drawing force of a conventional drawing process
Tandem drawing of wires and tubes is necessary because Annealing is needed between stages

The blank diameter used in thread rolling will be A little larger than the minor diameter of the thread.

Materials are limited to ductile materials because the threads are cold formed.
Also, materials with good deformation characteristics are necessary for rolling; these materials include softer (more ductile) metals and exclude brittle materials, such as cast iron.