Abstract: A lampshade is manufactured from heat deformable sheet material by forming a blank of the sheet material, in the shape of a sector of an annulus, into a hollow truncated cone having upper and lower peripheral edges. The overlapping edges of the blank are welded or bonded together and the blank supported by an apparatus which engages the interior of the conical blank, which apparatus includes an upper former for engagement with the interior surface of the blank adjacent the upper edge thereof and a lower support, releasably supporting a stiffening ring around its periphery, for example magnetically, so that upper marginal edge portion of the blank projects beyond the upper former and so that the lower marginal edge portion of the blank projects beyond the stiffening ring supported by the lower support.

Abstract: A lampshade is manufactured from heat deformable sheet material by forming a blank of the sheet material, in the shape of a sector of an annulus, into a hollow truncated cone having upper and lower peripheral edges. The overlapping edges of the blank are temporarily tacked together and the blank supported by an apparatus which engages the interior of the conical blank, which apparatus includes a former for engagement with the interior surface of the blank adjacent the upper and lower peripheral edges thereof so that marginal edge portions of the blank project beyond the formers. Heating means heat the marginal edge portions and upper and lower die members engage the heated and softened marginal edge portions to fold or roll the deformable sheet material around the edge portions of the formers and thereafter hold the formed edge portions in place until the material has cooled.