Center point marking instrument for use in drilling tool, has etching edges at mutually equal distances from midpoint of instrument for applying markings, where center lines intersect at midpoint of instrument

摘要

The instrument has a set of center marks (9) indicating a mid point (10) of the instrument for centering the midpoint of the instrument over a center point to be marked. Multiple etching edges (11) are at mutually equal distances from the midpoint for applying markings. A center line (13) vertically cuts each etching edge, where the center lines intersect at the midpoint of the instrument. The etching edges define slots for guiding a marking element. A pair of double arms (15, 15') is interlinked near the midpoint when the instrument is in use. Independent claims are also included for the following: (1) a drilling tool comprising a drill (2) a method for making marks on a surface.