This Mechanical Drawing is Detail Drawing of Countersink holes. A countersink (symbol: ?) is a conical hole cut into a manufactured object, or the cutter used to cut such a hole. Countersinking a screw mean, Also known as a flat-heat screw, a countersunk screw is a type of screw that's designed to rest flush with the object or surface in which it's inserted. They are called “countersunk screws” because they “sink” into objects and surfaces. To Specify countersink on a drawing, Write the dimensions of the countersink, giving first the diameter of the drill hole, then the angle of the countersink, followed by the diameter symbol and the diameter of the larger hole. This dimension can be given either with a diameter symbol first, or with the word DRILL after the first diameter. For more details and information download the drawing file.
