I gather the drill is grabing and stalling your drill..........
Blunten the cutting edge of the drill bit slightly with a honing stone or some emery tape etc.
it wont drill as quickly but it wont grab either
shouldnt be too hard to open 6mm out to 8mm that way even through 35mm plate..............
another trick is step your drill sizes up by small amounts to take smaller cuts untill you get out to 8mm...........