Quality is the best value：
Set of 7 pieces of M2 Screw Drill/Countersink/Counterbore bits combination units are specifically designed for woodworkers.
The high quality M2 pilot tapered drill bits are precisely ground on hand drill and match the shapes of wood screws so that screw threads grip for the entire length of the screw.
Because the pilot drill bit is detachable and can move up and down in the countersink/counterbore sleeve, it will let you set the unit for a wide range of drill depth to meet multi screw lengths.
The cutting angle of the 3 countersink chamfer cutters is 82 degrees, perfect for popular screw heads.
The counterbore is 10mm in diameter, 12mm in full depth; they are also sharp and hard
They will meet your needs from flush countersinking to a full 12mm of counterbore for dowel buttons or plugs.
Units are available for screw sizes 4, 6, 8, 10, 12, 14 and 16.
Pilot Drill Size 2mm for #4 Screw
Pilot Drill Size 2.5mm for #6 Screw
Pilot Drill Size 2.8mm for #8 Screw
Pilot Drill Size 3.2mm for #10 Screw
Pilot Drill Size 3.5mm for #12 Screw
Pilot Drill Size 4mm for #14 Screw
Pilot Drill Size 4.8mm for #16 Screw
For softwood, we recommend you to use a drill one size smaller than the screw calls for.