A way to put a bb rattle in a 68 mm long minnow.
I wrapped the rattle twice with soft wire, then twisted the wire just like a hook hanger, only that the twisted wire is very short, 4-5 mm long. After drilling the hole, I cut off the blank about half the place where the rattle would stay, and then I epoxied the wire together with the rattle.
My idea was to place the rattle as close to the head as possible, because the head (and tail) has the largest action in a crankbait, so that the ball inside would be smashed at the ends of the metal tube.
The lure is not unbalanced by the rattle, but I have noticed that it gained some roll as against the same lure without a rattle. I still have to experiment. I guess the fact that the rattle is concealed behind the lip is a good thing, because the water will not flow directly on the rattle.
I also will experiment this idea with a rattle at the tail.