EngineersHandbook.com and PortlandBolt.com are two sites that show bolt torque specification charts online. These charts indicate the estimated amount of torque to apply to the types of bolts indicated.
Torque is a twisting or turning force and differs from tension, which is a straight, pulling force. When an individual uses a threaded bolt to fasten two objects, the angle of the thread converts the torque being applied into tension in the shaft of the bolt. If the angle creates too little tension, the bolt can come loose; if the user applies too much torque, the bolt can fail. If someone’s safety depends on that bolt, the proper amount of torque to apply becomes important. Bolt torque specification charts are designed to help determine this amount.