Slingshot card ball how to open the hole bigger

1, first use sandpaper, roll the sandpaper into a tube, put it into the hole, rotate the sandpaper so that it rubs the wall of the hole to achieve the effect of expanding the hole. Be careful not to wear down the material around the hole when using sandpaper.

2, followed by the use of drills, the appropriate diameter of the drill bit into the hole, rotating along the hole wall, gradually expanding the diameter of the hole. It is important to note that when using the drill bit, care should be taken not to over-expand the hole, so as not to damage the structure of the card ball.

3, the last use of hot water: the card ball into the hot water soak for a period of time, when the card ball becomes soft, you can gradually expand the diameter of the hole by using your fingers or other tools. You can finish the slingshot card ball to open the hole bigger.