Abstract: A small expendable device for accurately and very quickly adjusting the verticality of door jambs without shingles or other shims. The device includes a body member which is attached to the rough wall opening and a carriage member which is attached to the door jamb and which is slideable in tracks across the body member. A Phillips screwdriver is placed in a tapered hole in the body between the tracks and its blades mate with a toothed edge of the carriage so that rotation of the screwdriver will force out or draw in the carriage. When locked, the door casing is applied over the door set device.