For maximum strength of the joint, it is important to select the correct length of silo bolt. Longer bolts have a shank, and if the shank is too long, this will stop the nut tightening before the joint is fully closed, and the bolt will spin, damaging the glass coating; a bolt that is too short will not have enough thread for the nut to grip properly. In the joint, the shank of the bolt should be in shear, not the threaded part of the silo bolt. To work out the length of silo bolt required, measure the thickness of all the pieces that will make up the joint.