on sierra 1ts a 19mm nut for wheels so m12 threaded stud

so the hole size in discs especially alloy bells what should this be?

obviously 12mm drill bit will be too small

ive lined up an m12 bolt with a pair of reyland bells i have it fits through fine but with a bit of play around the thread

is this alright,because the other ones i have have had a 14mm drill to make holes and therfore a bit side to side play,the centre circle fits tight on hub okay but the disc will move a little left to right until wheel is bolted on and pushing it tight

is this dodgy