Corrugated iron sheets are usually cut across the coiTiigation with a pair of bent-nosed snips; by using these, a good edge will be left after cutting, and the corrugation will be uninjured. Holes up to 1/4 in. in diameter are punched with a small solid punch; those of larger diameter with a hollow punch, the punching being executed on a lead piece; the burr left from the punching is afterwards worked down smooth with a square-faced hammer used on any convenient tool. The principal point to be observed when riveting is to make sure the rivet is tight drawn through with a rivet set before hammering it over.