Abstract: A method and apparatus are disclosed for automatically loading tape cartridges with supply tape. By this invention one tape cartridge can be wound with supply tape while simultaneously a second tape cartridge is prepared for loading with supply tape. The invention also relates to a novel shift block assembly for supporting, aligning, cutting and splicing two separate lengths of tape simultaneously. In another aspect of the invention a novel feeding assembly for controllably feeding tape cartridges to the winding position of the apparatus is disclosed.