We have index equation work bonds to jaw crusher ball,P80 = 25400 x Oss x (0.04Wi + 0.40) P80 = 25400 x Css x 7Ecc x (0.02Wi + 0.70) / (7Ecc – 2Css) Where Oss = Open-side setting in inches. Css = Closed-side settings in inches. Ecc = Eccentric throw in inches. P80 = Aperture through which 80% of the product will pass. Wi = Work Index.