10 essential hand tools
5 of 10
Photo by iStockphoto/Thinkstock
Engineer's Square
This tool is the ultimate representation of 90º in my shop. Small yet unequalled for machine setup, the square I use is accurate to within 0.001" over the length of its blade. I have two 4" squares: one stays in my apron, and the other is stuck to a rare-earth magnet on my jointer, which also is right next to the tablesaw and easy to grab for setting up machines.