Ok I'm building sleeper walls in the garden and I need a new drill. I'm drilling a 6mm hole through the sleeper and into the supporting post, but the longest drill but I can find is 150mm which just isn't long enough, as soon as the screws I'm using hit the raw wood the drill jams and I have to use the drill as a makeshift screwdriver, which has caused me to burn the motor out. So new drill is needed, and I have no idea if I need a corded hammer drill or a more powerful portable drill, one I've been using us only 14.4v. Any help would be much appreciated?! Edit: just ordered a 6mm x 235mm drill bit so that's half the problem solved. So basically most cordless drills are 18v, will that be sufficient?