Or use a jigsaw. The cutting tool, not the cardboard pieces.
Or sheet of hardboard and a stanley knife, which is probably the most sensible option in context.
Or sheet of hardboard and a stanley knife, which is probably the most sensible option in context.
All in all when I needed a one-off cut I used a box cutter knife, and when I needed a series I used a circular saw with a plywood blade. The setup is similar (needs an offset guide) but the cut is much straighter, faster, and less error prone. I think the only time I'd use a jigsaw is for making non-straight cuts like some curved artistic shape or something.