[Closed] Drilling out chainring bolts?

I've used a HSS bit, and just gradually increased the size. So, start with whatever makes contact, probably about 3mm, drill that through, then increase to 4mm etc.

You only need to drill the head off the bolt so start small, but don't bother drilling right through each time, you only need to reach the threads under the head.

as above, use a large bit at low speed to take the head off far enough that it comes off - you don't need to actually drill through the whole bolt.

use a pillar drill if you have access to one - you have so much more control