Prado Unifit Forstner Bit

Drill with care. For best results, apply painter's tape over the area to prevent tear-out, then use a drill press for accurate alignment and clean edges. If using a handheld drill, keep it perpendicular to the surface. Always test on a scrap piece of wood before drilling the final workpiece. For flush installations, drill the 1-1/2" (Ø38 mm) countersink to a depth of 1/10" (2.5 mm), followed by the 1-3/8" (Ø35 mm) hole, ensuring both remain perfectly centered by not moving the workpiece between steps. Drill at moderate speed and avoid excessive pressure.

Alternatively, the countersink can be cut with a rabbeting router bit, for both single and duplex. Set the bit depth to 1/10" (2.5 mm) and rout around the pre-drilled or milled opening using a router table or plunge router. This method offers consistent depth control and clean edges, making it a great option if you have a router available.