NEVER. You mark with pencil the hole’s location and then use the brad point Drill bit that we have included with our jigs to drill precision holes. Some jigs in the market allows the user to clamp the jig to the drawer or door and drill through the jig.  Our philosophy is different. Drilling through the Jig is a very risky task.  Even a slight movement can screw up the hole position and spoil expensive cabinets.  Our jigs encourage the user to mark the hole positions with pencil, do a dry run to make sure everything looks fine before the actual drilling.  This two steo process eliminates the chance of drilling holes in the wrong location and spoiling expensive cabinets.