Like in the “bullseye” target, to get to the center of the end face of the cylindrical body of rotation help simple tool, consisting of only two parts. They can make plastic, metal or solid wood. Made in one rectangular cutout, and the other is a line imposed on the first item on the bisector of the angle cut. Method of connection of both parts depends on the material. Attach the tool neck to the cylinder and slide on the line a small bar, then slightly rotate the cylinder and put another line in their intersection is the required centre.