Drilled hole dimensions are shown by the use of a leader and a note. These are usually applied to the view that shows the shape of the hole. The note gives the size of the drill, the number of holes to be drilled, and may also give the depth to which the holes are to be drilled. Holes with no depth dimension are to be drilled all the way through. However, this may also be indicated by adding the word “thru” to the drill size dimension.

Note that the hole depth may be indicated by the abbreviation DP for “deep” or the depth symbol. A drill size can be given as a letter size, a number (wire gage) size, a fractional size, or a metric size. Figure 4.10 illustrates the various methods for dimensioning drilled holes.