The 6 simple machines: Lever Wheel and axle Pulley Inclined plane Wedge Screw Read more: http://www.survivalmonkey.com/forum/back-basics/32931-basic-tools-pulleys.html#ixzz1v8pyheZc There are lots of uses for inclined planes. One of them is a screw/hand auger/bits. Amazon.com: Fuller Tool 890-1071 12-Point Reversible Ratchet Brace with 2-Jaw Chuck: Home Improvement If the SHTF, how are you going to build stuff? You'll need things like: handsaw hammer nails (tip inclined plane) hand plane hand auger/bits screws (inclined plane) shovel axe (another inclined plane) mattock/pick-axe chisel (with a way to sharpen) (and another) files crowbar (lever) drawknife What about lumber? A guy with a portable sawmill would make a mint (provided there was some law and order) Poor Boy's Sawmill - YouTube Band Saw Mill.wmv - YouTube The six simple machines is also something good to get your kids involved with. There are tons of stuff on the net for kids on this top. Teach them now and play games to keep them looking for things that are simple machines. It will pay off later.