Why make a drill hole in a dart

Drill holes in darts or other areas of the pattern piece is a marking technique used to show the Machinist the placement of the dart, where to start and end the dart and how wide to sew the dart. Drill holes are also used to show placement of pockets, tucks, pleats and other design details. The Machinist will usually sew .6mm past the drill holes for the width of the dart and the length of the dart may vary, which is usually stated on the pattern. Drill holes for pockets are usually placed .6mm in from the pocket placement. Drill holes are made on pattern pieces using a special device or even an awl can mark a drill hole.