Is it possible to fit a hex shank drill bit (masonry) onto a 3 jaw chuck ?
It depends on the shank. Some masonry bits have a round area too close to the hex to fully lock a drill chuck on (oem bits for specific brands). If the shank is a full hex it will work with no problems. I use hex bits all the time because they grip better in the drill chuck and don't take as much force to hold them in place so they won't spin when you bite into a tougher spot.