Quote Originally Posted by tankproof2 View Post
Hi guys, im looking to make a bunch of 3-4mm holes in aluminium (6061) but i understand drills are kind of out off the question due to the spindle speed being too high. so my question is how should this be done? I could buy some smaller 1-2mm endmills and machine them out but i feel this will just leave me with a bunch of snapped mills and end up costing a fortune, my router is running flood cooling if that helps at all and has a standard 2.2kw Chinese spindle on it.

thanks in advance Oli
4mm will be no problem, I drill 4.2mm (m5) holes all the time in aluminum with a 2.2Kw spindle, just use a peck drilling strategy. For the 3mm holes, I would start them first with a spot drill because a smaller drill can wander off.