Marking Gauge Marking Gauge Here's a nifty way to trace cutting or drilling lines on workpieces: First drill a 1/8-in. pencil hole 1 in. in from the ruler end of a combination square and adjust the square to the desired dimension. Then stick in the pencil and pull the square along the board edge to trace the line. Be careful to drill a hole that's only a smidgen larger than the pencil point. You'll be able to speedily produce straight, crisp lines for all kinds of jobs.