Flat washers are thin round pieces of metal, usually steel, which have a hole through the center and are used to spread the force under a bolt head or nut. Flat washers are used extensively in automotive and mechanical operations, often in conjunction with a split washer, also known as a lock washer. The process of using a flat washer is quite simple, but knowing when to use one is important.
Select a flat washer that just fits over the thread of a bolt and place it on the bolt.
Insert the bolt in a hole drilled through the material to be fastened. The hole can be a through-hole, or one threaded to receive the bolt.
Tighten the bolt in the hole if the hole is threaded. In the event of a through-hole, place a second flat washer on the end of the bolt and then a lock washer if needed and finally the proper-sized nut to fit the bolt.
Tighten the bolt and nut with wrenches.
Use one flat washer when the receiving hole is threaded and two when bolting two or more pieces together or if the material being secured is soft or slotted. Flat washers prevent the nut and bolt from digging in the the soft material or slot edges.
