The shear strength of a grade 8 bolt is 90,000 psi, assuming the bolt is between 1/4 inch to 1 inch. Shear strength is typically estimated to be 60 percent of tensile strength. The tensile strength of a grade 8 bolt is at least 150,000 psi.
All grade 8 bolts have the same tensile strength per square inch. Thus, the larger the bolt, the stronger the tensile strength of the bolt. Shear strength must be calculated, because the American Society for Testing and Materials does not require shear strength values to be published. To calculate tensile strength of a bolt, the tensile stress area should be multiplied by 150,000 psi.