Magnetic caliber square

1、Application
To precision measure the inter/external diameter of roundpiece
2、Operation 
1) one side of the obje ct was adsorbed by left-magnet,and fixed with the steel ruler.
2)Another side of the object was adsorbed by right-magnet, take the steel ruler into the vernier and through out the holder, then tight steel ruler,locked with pressure’ screw.
3)Let right-magnet depart the object by adjustment reduce magnetic screw, observe the change of the dialgage , and then find the symmetric points.
4) By adjust the reduce magnetic screw, let right-magnet  and the obje ct full contact.Twist the dynamometry nut, make dynamometry mark reach the assigne d point, let steel ruler up to the standard 
5) reading vernier
3、Attention
1) Finished measurement, loose dynamometry nut firstly!
2)Never loose keeping steel ruler, Prevent distortion.
3)be care of water, never kept with Corrosive!