I live in an old cottage built in churt, a form of flint, bonded with lime mortar. The stone is very hard which makes fixing things to a wall a challenge. The traditional method which works well is to excavate holes in the mortar joints, drive in wooden pegs, and screw into those. This is easy outside, but inside it is another story requiring many test drillings to find a suitable mortar joint, but which is unlikely to be in or near to the required location. Does anyone have any other suggestions? Is it possible to drill into the stone? Normal masonry drills just skate off the surface.