If you have ever fixed anything, you have probably used washers and bolts. They tighten and secure just about everything, from wood beams to alternators. Washers and bolts appear to be simple, but people often misuse them. To get the most out of washers and bolts, and to make every bolt connection more secure, it is wise to learn how to use them correctly. Each has a specific function and should be used exactly as intended.
Size the bolt to the mounting hole. Check the proper size of the mounting hole through the manufacturer's documentation, then find the right bolt sized to that hole. If the hole does not specify a diameter, try different sized bolts until one fits perfectly in the hole.
Size the washer to the bolt. The washer fits around the shaft of the bolt, and slides all the way up to the bolt head. No friction should exist between the washer and bolt.
Insert the bolt into the washer first, then slide the bolt and washer into the mounting hole. Once the bolt is threaded into the hole, begin turning the head of the bolt using the appropriate sized wrench. Tighten the bolt down to the washer until the head contacts the washer.
Tighten the bolt with a torque wrench, if specified in your installation. Place the torque wrench over the head of the bolt, and turn it until the torque wrench pops and gives you a reading. When the reading matches the proper torque required for your assembly, the bolt and washer are properly tightened.