The dust port on my contractor’s saw is below the blade arbor, and more than once I’ve dropped the arbor nut down inside the hole when changing blades. It was really frustrating until I devised a simple fix: I place a piece of stiff wire hardcloth over the dust port before I remove the nut. The edges are covered with duct tape to protect my hands. When it’s in place, the nut has nowhere to hide! Once it’s threaded back on the arbor, I pull out the wire “trap” and store it with my blade-changing wrenches.