No experience with Chronos, but I bought a set of tin coated drills in a metal hinged box from LIDL
and the first job I had to do with them was drill 10 off 10mm holes through the edge of a heavy duty steel staircase. Not only did they go through it like butter, but the drill was unmarked when I put it back in the box. Still use them and can't fault them! 1mm to 12mm set for £9-99, can't find a link to them, but watch out in yer local lidl.
Phil