A 1.5 inch thick steel plate and a 0.5 inch thick cast iron plate are compressed with 1/4- 20 UNC grade 5 bolt and standard nut in an assembly that is routinely taken apart for servicing and inspection. Determine a suitable length for the bolt, rounded up to the nearest 1/4 inch. What percentage of an external load on the assembly will be supported by the bolt? What external load will cause separation of the joint?