You're running large-diameter pipe or conduit through floor joists and wall studs, and the 3/4-inch hole isn't enough — but your 1-inch spade bit is wandering across the surface on first contact and producing an oversized, wobbly hole. Starting clean is the difference between a good hole and a damaged stud. 7/8-inch diameter, 16-inch length — covers the most common large pipe and conduit sizes (3/4-inch and 1-inch PVC, EMT) without being oversized. 16-inch overall length reaches through multiple studs or joists in a run without an extension. The tip design on Irwin spade bits starts faster than basic spade bits — reduces walking and surface damage on the first contact. Heavier-gauge steel body resists bending under lateral pressure when you're drilling at an angle or through dense stock. S Stocked at Crofton Lumber and Akron Lumber.