Make an arbor wrench, for a table saw or other tool, using a carpenter square.
Step 1: Carpenters Square
Grab a cheap, but strong carpenter square that is wide enough to accommodate the arbor nut on your tool. Choose steel over aluminum.
Step 2: Mouth
Cut away material at one end of the square the width of the arbor nut.
Step 3: Torque
Ready for use.