Complex sentence: During World War II Sprague operated around the clock and employed a large workforce of women-not only because of the lack of men, but because it took small hands and manual dexterity to construct the small, hand-rolled capacitors.
Split into simpler sentences: During World War II Sprague operated around the clock and employed a large workforce of women. Sprague did not employ women just because of the lack of men, but because it took small hands and excellent manual dexterity to construct the small hand-rolled capacitors.