It is generally best to use washers with bolts, because this spreads out the holding force of the bolt over a greater surface area for the pieces being bolted together. This makes it much less likely that the bolt will pull itself through the hole and cause the joint to fail. Also, washers keep the action of tightening the nut from marring the surface of the work and make it easier to get the nut tight. You should always turn the nut, not the bolt, especially if the bolt is holding together steel pieces. This helps protect the threads on the bolt from becoming damaged. Regular washers are generally known as flat washers. Split-ring washers and tooth washers may be used where vibration is a problem. These types of washers keep tension on the nut at all times and prevent it from working itself loose. parts together. Anything that hangs overhead should be bolted for safety reasons, and if there is any question at all about the weight of the piece, be sure to use rated bolts and other hardware. This is especially true when the load is pulling on the fastener along its length. A sideways force creates a shearing stress, which is gener- ally less likely to pull two wooden structures apart, because that would require the total failure of the wood