Due to the snow last week, we left our trailers parked and thought we had what we needed at a condo rehab we are doing. Anyway, we forgot hole saws to cut shower valve openings for the 1/2 hardibacker. Instead of going to get the hole saw, We improvised by driving a screw every 1/2" around a circle then just punching it out to get that perfect hole. Gave us a clean hole, no dust, and was quick. Anyone got other good improvising tips they have used?