Nuts and bolts are useful when you need a strong joint, […]
Nuts and bolts are useful when you need a strong joint, when you might be taking the item apart later and when joining two pieces of metal or other thin materials. As with any fasteners, it's important to choose the right ones and install them properly.
There are three major types of bolts:
* Machine bolts are made with unslotted square or hexagonal heads that accept a wrench and are used with either square or hex nuts. These bolts are available with fine threads, but coarse threads are more common.
* Carriage bolts have unslotted oval heads with a square shoulder beneath the head and are designed to be used with wood. The square shoulders sink into wood to keep the bolt from turning when a nut is tightened onto it. Carriage bolts have coarse threads.
* Stove bolts have slotted heads that are round, oval or flat and accept screwdrivers. They have coarse threads and are sold as general utility bolts. In smaller sizes, they are called machine screws and may have either fine or coarse threads.
To install a bolt, slide it into place and screw the nut on clockwise. Once the nut is partly on, hold the bolt head stationary with a wrench or a screwdriver (if the bolt head is slotted). Turn the nut by hand until it is snug.
If a nut is too worn to grip with a wrench, apply locking pliers as tightly as possible. If this fails, file two sides of the nut flat, then try the locking pliers again or an adjustable wrench.
If a hex nut or bolt is rusted or frozen, apply penetrating oil. Let it sit for a few minutes, then try the wrench again. Repeat if necessary.