These pilot drill bits from Black+Decker have a 1/4in hexagon drive.
89-1707
Sealey DPG99 Drill Press Guard 60mm
Only£19.38
89-1704
Sealey DPG250 Drill Press Guard 92mm
Only£34.49
89-1705
Sealey DPG30 Drill Press Guard 40mm
Only£14.00£11.67
86-2388
Bosch 2608600218 Metal Grinding Disc 115 x 22.2 x 6mm
Only£2.00
86-2605
Fortex CBD3818/080 Carbide PCB Drill Bit 0.8mm
from only£2.65