TSA-friendly Craft Knife

I'm an artist and I like to have a craft knife when I travel - something sturdy enough to use against a straightedge. But I fly light and often don't have bags to check. In the past I've purchased craft knives/blades at my destination (blades of which have to be tossed if I'm not checking bags on my way back). This solution is not quite as good as a real craft knife, but it's good enough for light-duty work.