I use a lot of these disposables for drilling http://www.mscjlindustrial.co.uk/CGI/INPDFF?PMCTLG=13 Page 9 FC3 Hertel longs cheap £2.2 each region and last surprisingly well compared to more expensive 6 to £7 ones up to 6mm.
1mm scary but used to use the 1.5mm longs ground away at shank on Dickson round action tumblers, Robin will know what i mean tool steels.