The design and fabrication of a large shear plate is presented to obtain a large shear. The shear plate consists of two glass plates separated with a large air gap. The two glass plates are held rigidly with three spacer rods. The inner surfaces of the glass plates are made nearly parallel to each other. The shear is obtained after reflection from the two inner surfaces. A shear plate assembly of diameter 200 mm has been built to obtain a maximum shear of 50 mm. This shear plate assembly is found to be useful for testing lenses and for checking the laser beam collimation of an aperture 100 mm with a higher sensitivity.