The failure point on any spade bit is chip packing — the flute loads up with chips at depth, the bit grabs, heat builds, and either the bit dies or the walls of the hole get torched. In harder lumber or deeper drilling, it happens fast and it costs you time and battery. 7/16-inch diameter covers the smaller wire-pass and fixture holes that framing and trim crews drill constantly. The flat blade with a higher flute than standard spade bits moves chips up and out faster — less packing, fewer stalls, lower heat at depth. The higher flute design is what separates Speedbor from basic spade bits — faster self-feeding action that keeps the bit cutting rather than wedging in the hole. 1/2-inch reduced shank fits every standard drill chuck. Standard on framing crews and rough-in carpenters across n Stocked at Crofton Lumber and Akron Lumber.