Screw Gauge, Metric, Size, Clearance Holes, Pilot Holes & Wall Plugs I’ve explained this screw data in an easy to understand table because I find manufacturers recommendations are often vague and general, I mean; why not be specific? I understand there’s a ‘range’ but why not give us the ‘ideal’ measurement, because mostly we have a choice? The table below shows you: Metric equivalents to imperial gauge. What size pilot hole to drill in timber substrates for the best screw grip. What size clearance hole to drill through the timber being fixed. …
