Abstract: Apparatus and method for twisting thin strip material such as thin aluminum strip in which the strip material is guided from a supply of strip material along a feed path 21 to a guide mechanism 11 which maintains the strip in a first plane and is then passed to two rolls 31, 32, at least one of which is driven. The rolls have on their outer circumferential edges 33, 34 grooves 41 which grip opposite edges of the strip, the rolls 31, 32 being mounted so that their axes of rotation are twisted with respect to one another whereby the strip is driven forwards by the rolls 31, 32 and twisted as it passes through the rolls to form a helically twisted strip.