Abstract: A portable machine for the production of siding of alternative cross sectional configurations from metallic stock, the siding of both configurations being of equal width and including butts adjacent their lower edges and marginal portions shaped for interfitting engagement with marginal portions of adjacent siding strips when the strips are laid. The strips of one configuration have only the lower butt and the strips of the other configuration have an additional intermediate butt. The machine includes a series of spaced pairs of upper and lower shafts, said shafts supporting opposed rollers having shaping elements for gradually shaping the lower butt and the marginal portions of the stock, and certain of said shafts additionally supporting mounting means intermediate said spaced pairs of upper and lower rolls for the support of readily attachable and detachable shaping elements for forming said intermediate butt when desired.