Abstract: A method of lining a cylindrical bore for instance of an internal combustion engine with a thin-walled liner. Initially, a strip of material is cut to such a length that when formed into a cylindrical liner of external diameter equal to that of the unlined bore the liner is subjected to hoop-stress. The cut strip is pressed into a semi-circular groove in a jig-plate with a mandrel of at least part-circular form, and then two jig cheek-pieces each defining a quadrant-shaped groove are moved to deform the strip into a cylindrical shape. During this, the strip is held in the groove in the jig-plate for instance by electromagnets let into the jig-plate, or by a vacuum-holding technique. The grooves respectively in the jig-plate and jig-cheek pieces together define a cylinder of the same diameter as the bore to be lined, so that the liner is subjected to hoop-stress while in the jig.