Abstract: A process is provided for assembling a laminated iron core on a support structure about an electric coil from a plurality of laminations to form a shell-type transformer core. According to the process, the plurality of lamination sections are stacked in a staggered relationship to form a first core section which has joint ends to form overlapping joints between an adjacent core section. The first core section is stacked by placing a slider sheet of a low coefficient of friction on a first support member and stacking the lamination sections on the slider sheet. The first core section is then conveyed onto the support structure at which the iron core is to be assembled, and the slider sheet is pulled out to cause the first core section to directly sit on the support structure. The plurality of lamination sections are inserted between the joints on site to form a second core section which connects the joint ends of the first core section to define a magnetic circuit around the coil.