Fasten the mounting nut lightly and line up one row of tuners with the help of a rule. Pre-drill each hole for the small mounting screw with a 1/16" (1.5mm) bit. A piece of tape on the bit can serve as a visual depth stop to prevent drilling through the peghead. Now fix the tuner positions with the small screws. Tuner mounting screws have a round Philips head and require a Philips PH1-2 screw driver. Fasten the tuner mounting nuts with a wrench. A common key size is 10mm.