Every item on this page is carefully selected by the editor of House Beautiful. We may earn commissions on certain goods you choose to purchase.

Don't be messed up by the wrong material.

It seems that trying to use the brand's instructions to make a piece of IKEA furniture is difficult enough. When you don't know what any material is, it's almost impossible. Of course, you know what wooden dowels are, but which small bag has hexagonal bolts? Do you need nuts? All these issues add unnecessary pressure to an already complex situation. That chaos is now over. Roy Berendsohn, senior editor of Popular Mechanics, shared a quick course on fasteners. According to Roy, the following is a breakdown of the seven most common types of screws and bolts that every homeowner will encounter at some point in his or her life.

Hexagonal bolts or hexagonal cap screws are large bolts with six-sided (hexagonal!) heads that are used to fix wood to wood or metal to wood. "Unlike carriage bolts, when you tighten them, they have a tendency to rotate, so you need to fix the bolt head with a wrench or socket, and then use a second wrench to tighten (or loosen) the nut," Roy said. Hexagon bolts have small threads and smooth shanks, and can be ordinary steel for internal projects, or stainless steel or galvanized for external use.

Wood screws have threaded shafts for fixing wood to wood. These screws can have several different threads. According to Roy, when tightening softwoods such as pine and spruce, it is best to use wood screws with fewer threads per inch of length. On the other hand, fine-pitch wood screws should be used when connecting hardwoods. There are many different types of heads for wood screws, but the most common are round heads and flat heads. "The head of the round head wood screw is completely above the work piece. The head of the flat head wood screw is embedded in the work piece," Roy explained. Wood screws can be ordinary steel, brass, stainless steel, or weather-resistant steel.

Sheet metal screws are used to fix two pieces of sheet metal together, or to connect the sheet metal to other types of metal, such as pipes. These screws usually have round, flat, or even hexagonal heads. Roy said the thing to remember about sheet metal screws is that they are thread cutting types. He explained: "The shape of the screw tip allows the thread to be cut into the receiving metal where the screw is driven," adding that they are often referred to as "self-tapping" screws. They are almost always ordinary steel, ordinary steel with weather-resistant coating, aluminum or stainless steel for maximum weather resistance.

Machine screws are a mixture of small bolts and screws, used to fix metal to metal or between metal and plastic. At home, they are used to fix electrical components, such as connecting lamps to electrical boxes. In such applications, a machine screw is screwed into a hole, and a matching thread is cut or "tapped" in the hole. Roy said that if the hole is not tapped, the machine screw needs a nut.

Hexagon socket screw is a kind of mechanical screw whose cylindrical head can accommodate socket wrench. In most cases, these screws are used to fix metal to metal and need to be tightly installed to ensure a secure connection. They are usually used in situations where items may be disassembled and reassembled over time.

Square-head bolts, commonly known as square-head screws, are usually large in diameter and long enough to penetrate the wood to form a firm connection. The possibility of loosening the screw after tightening is small. Common locations where such screws can be found are decks, docks, and wooden retaining walls. Due to the corrosive nature of pressure-treated external wood, the lag screws have a corrosion-resistant coating. "They are hot dipped in zinc or made of stainless steel," Roy explained.

Carriage bolts, which can be considered the cousins ​​of lag screws, are large bolts used with washers and nuts to hold thick wood blocks together. Below the round head of the bolt is a cube-shaped extension that cuts into the wood and prevents the bolt from turning when the nut is tightened. This makes it easier to turn the nut (you don't have to fix the bolt head with a wrench) and prevents tampering. "The nut is almost always on the back of the component. Therefore, once tightened, the fastener cannot be loosened easily, because the head of the carriage bolt is round-like an old rivet-and you can't easily use pliers. Grab it or the wrench," Roy explained.