Sliding mechanical special staff gauge for placket degree

The utility model relates to a special ruler used for measuring the opening degree of a sliding machine. The special ruler is characterized in that the ruler is made of a piece of steel plate, at the top of which, a bulge is arranged. The bulge is mated and connected with a positioning thrust terminator arranged in a tundish sliding machine body; and the edges of the left end and the right end of the steel plate are mated and connected with an oil tank sliding channel arranged on the tundish sliding machine body. The special ruler has simple structure and not only can measure the opening degree of a sliding machine, but also can alleviate the deformation of the sliding machine caused by scraping and colliding during the transportation.