help needed boring 8mm holes 20mm depth in Alu

[magicniner]

The 1/8" single flute bits I use for Aluminium alloys, brass and bronze are advertised for engraving and plastics use, I sharpen them with a little more relief and I've yet to have one chip or break, attached is a photo of a prototype linear tracking air-bearing tone arm I profiled from solid with a 6mm uncoated single flute bit, air to clear chips and a little squirt of lube every few passes and the bits just keep on running,
Regards,
Nick